What exactly is COALESCE in SQL Server?
Answer: COALESCE returns the first non-null expression in the arguments. This function returns a non-null value from more than one column in the arguments. Example – Select COALESCE(empno, empname, salary) from employee;What are the distinctions between local and global variables?
Answer: Local variables are variables that can only be used or exist within the function. No other function uses or refers to these variables.In SQL Server programming, how are exceptions handled?
Answer: SQL Server handles exceptions with the try and catch block.BEGIN TRY --code which might raise exception END TRY BEGIN CATCH --code to run if error occurs in try block END CATCHThe try block contains code that may throw an exception. The catch block contains the code that is executed if an exception occurs in the try block.
BEGIN TRY
--divide-by-zero error
SELECT 5 / 0 AS Error;
END TRY
BEGIN CATCH
SELECT
ERROR_NUMBER() AS ErrorNumber,
ERROR_STATE() AS ErrorState,
ERROR_SEVERITY() AS ErrorSeverity,
ERROR_PROCEDURE() AS ErrorProcedure,
ERROR_LINE() AS ErrorLine,
ERROR_MESSAGE() AS ErrorMessage;
END CATCH;
What exactly is Black Box Database Testing?
Answer: Black Box Testing is a software testing approach in which the functions of software applications are tested without knowledge of the internal code structure, implementation details, or internal routes. Black Box Testing is a type of software testing that is entirely driven by software requirements and specifications and focuses on the input and output of software applications. Another term for it is behavioral testing.What are the benefits of using Stored Procedures?
Answer: The following are the benefits of using stored procedures: The use of stored procedures improves application performance. Because stored procedure execution plans are cached in SQL Server’s memory, they can be reused, reducing server overhead. They are reusable. It is capable of encapsulating logic. The stored procedure code can be changed without affecting clients. They improve the security of your data.In SQL, how do you delete a table?
Answer: SQL has two methods for deleting tables: DROP and TRUNCATE. The DROP TABLE command is used to remove a table from the database entirely. The command is as follows:DROP TABLE table_name;DROP TABLE table_name ;What exactly is TCL in SQL Server?
Answer: TCL stands for Transaction Control Language Commands, and it is used to manage transactions in SQL Server.What exactly is de-normalization?
Answer: It is the process of attempting to improve a database’s performance by inserting redundant data. De-normalization is the intentional introduction of redundancy in a table to improve performance. The de-Normalization process improves read performance while degrading write performance. It is possible to accomplish this by creating a group of data in the redundant form. The un-normalized and de-normalized databases are diametrically opposed. Any database should be normalized first before proceeding with the de-normalization process.What exactly is identity in SQL?
Answer: In SQL, an identity column generates numeric values automatically. We can be defined as the identity column’s start and increment values. Identity columns do not require indexing.What is the purpose of Views?
Answer: A view is a logical snapshot of a table or another view. It is employed for the following purposes: Restricting data access. Making complex queries easy to understand. Providing data independence. Providing various perspectives on the same data.In SQL, how do I view tables?
Answer: To view tables in SQL, simply enter the following command:Show tables;
How does a table’s table type constraint work?
Answer: The Table Type Constraint is used as follows: Change the Constraint’s Table Name Table Constraint 1 should be changed.Describe the various index configurations for a table?
Answer: A table can have the following index configurations:- A clustered index:When there is only one clustered index.
- A non-clustered index:When there is only one non-clustered index.
- Many non-clustered indexes:When there are multiple non-clustered indexes.
- A clustered index and a non-clustered index:When there is a single clustered index and a single non-clustered index.
- A clustered index and many non-clustered indexes:When there is a single clustered index and more than one non-clustered index.
- No index:When no indexes are present.
What is the recovery strategy? What are the different types of recovery models available in SQL Server?
Answer: The recovery model specifies which data should be retained in the transaction log file and for how long. There can only be one recovery model in a database. It also informs SQL server about which backups are possible in the selected recovery model.What are the fundamental SQL skills?
Answer: SQL skills help data analysts create, maintain, and retrieve data from relational databases, which are divided into columns and rows. It also allows users to retrieve, update, manipulate, insert, and alter data with ease. The following are the most fundamental skills that a SQL expert should have:- OLAP Skills
- Using WAMP with SQL to create a database
- Structuring a Database
- SQL System SKills like MYSQL, PostgreSQL
- PHP expertise is useful.
- Database Management
- Analyze SQL data
- Creating SQL clauses and statements
- Full
- Simple
- Bulk-Logged
What are SQL Server scheduled tasks?
Answer: SQL Server scheduled tasks are predefined steps or tasks. These tasks are automated by SQL Server Agent. It runs them sequentially and at a predetermined time.How and what command is used to create a database in SQL Server?
Answer: To create a database in SQL Server, use the CREATEDATABASE command. Syntax: CREATEDATABASE Database name For example, if the name of a database is “employee,” then the command to create this database is CREATEDATABASE employee.How and what command is used to delete a table from a SQL Server database?
Answer: The DELETE command is used to delete any table from a SQL Server database. DELETE The name of the table For example, if a table’s name is “employee,” the DELETE command to delete this table can be written asDELETE the employee.
What exactly is a join in SQL?
Answer: Joins are used to combine rows from two or more tables based on a common column. Joins of various types: INNER JOIN returns rows when both tables have a match. • LEFT JOIN returns all rows from the left table, even if no rows from the right table match. • RIGHT JOIN returns all rows from the right table, even if no rows from the left table match. • FULL OUTER JOIN returns rows when one of the tables matches. • SELF JOIN Used to join a table to itself as if it were two tables, renaming at least one table in the SQL statement temporarily. • CARTESIAN JOIN (CROSS JOIN) Obtains the Cartesian product of the records from the two or more joined tables.How do you conceal SQL Server instances?
Answer: To hide the SQL Server instances, you must make a change in the SQL Server Configuration Manager. Follow the steps below to launch SQL Server Configuration Manager and perform the following actions: Select the SQL Server instance. Select Properties from the context menu. After you’ve chosen your properties, simply set Hide Instance to “Yes” and click OK or Apply. After making the change, you must restart SQL Server in order to avoid exposing the instance’s name.What exactly is a SQL example?
Answer: SQL is a query language for databases that allows you to edit, delete, and request data from them. The following are some examples of SQL statements: SELECT INSERT UPDATE DELETE CREATE DATABASE ALTER DATABASEWhat are the distinctions between a stored procedure and dynamic SQL?
Answer: A stored procedure is a collection of statements that are stored in compiled form. Dynamic SQL is a set of statements that are created dynamically at runtime, are not stored in a database, and are only executed during runtime.What are the most common SQL Server performance issues?
Answer: The following are some of the most common performance issues: Fragmentation Missing and unused indexes. I/O bottlenecks Deadlocks Blocking Poor Query plansWhat exactly is COALESCE in SQL Server?
Answer: COALESCE returns the first non-null expression in the arguments. This function returns a non-null value from more than one column in the arguments. COALESCE accepts all values but returns only non-null values in the expression. Syntax:COALESCE(expr1, expr2, expr3,......,expr n)
What exactly is the distinction between NOW() and CURRENT DATE()?
Answer: NOW() returns a constant time indicating when the statement began to execute. (Within a stored function or trigger, NOW() returns the time the function or triggering statement started executing. The only difference between NOW() and CURRENT DATE() is that NOW() returns the current date and time in the format ‘YYYY-MM DD HH:MM:SS’, whereas CURRENT DATE() returns the current day’s date in the format ‘YYYY-MM DD’.What command is used to recompile the stored procedure during runtime?
Answer: RECOMPILE is a keyword that can be used to execute a stored procedure. ExampleExe <SPName> WITH RECOMPILEOr we can include WITHRECOMPILE in the stored procedure itself.
What’s the distinction between COMMIT and ROLLBACK?
Answer: When the COMMIT statement is executed, every statement between BEGIN and COMMIT becomes persistent in the database. Every statement between BEGIN and ROOLBACK is reset to the state it was in when the ROLLBACK was executed.What exactly is a Self-Join?
Answer: A self-join is a type of join that can be used to join two tables together. As a result, the relationship is unary. In a self-join, each row of the table is connected to itself and all other rows of the same table. As a result, self-joins are typically used to combine and compare rows from the same database table.What exactly is the SELECT statement?
Answer: A SELECT command retrieves one or more rows from a database table or view. In most applications, the most commonly used data manipulation language (DML) command is SELECT. Because SQL is a declarative programming language, SELECT queries define a result set but not how to calculate it.What is the distinction between varchar and nvarchar data types?
Answer: Varchar and nvarchar are the same thing; the only difference is that nvarchar can store Unicode characters for multiple languages and takes up more space than varchar.What is the maximum number of indexes allowed per table?
Answer: For SQL Server 2008, the maximum number of indexes per table is 100. SQL Server supports 1 clustered index and 999 non-clustered indexes per table. The maximum number of indexes per table is 1000. SQL Server supports 1 clustered index and 999 non-clustered indexes per table. SQL Server supports 1 clustered index and 999 non-clustered indexes per table.What exactly is SQL Server?
Answer: SQL Server is a relational database administration system. It provides data storage and retrieval functionality to applications. On April 24, 1989, Microsoft released SQL Server. SQL Server comes in a variety of editions that cater to different audiences.What exactly is a full backup?
Answer: The most common type of backup in SQL Server is a full backup. This is a full backup of the database. It also contains a portion of the transaction log, which can be recovered.What is the difference between “scheduled jobs” and “scheduled tasks”?
Answer: Scheduled tasks allow you to manage tasks in an automated fashion that runs on regular or predictable cycles. You can schedule administrative tasks and also specify the order in which they will be executed.What Exactly Is SQL Profiler?
Answer: SQL Profiler is a tool that allows system administrators to monitor SQL server events. This is primarily used to record and save data about each event in a file or table for later analysis.Can SQL Server communicate with other servers, such as Oracle?
Answer: Yes, it can connect to any server. It has a Microsoft OLE-DB provider that allows for linking.What exactly is mirroring?
Answer: Mirroring is a solution for high availability. It is intended to keep a hot standby server that is transactionally consistent with the primary server. Transaction Log records are sent directly from the primary server to a secondary server, which keeps the secondary server in sync with the primary server.What’s the distinction between an application object and a session object?
Answer: The session object is used to keep track of each user’s session. When a user enters an application, he is assigned a session id, which is then deleted when the user exits the application. If he enters the application again, he gets a different session id, but for application objects, once an ad id is generated, it keeps the entire application.What are the three methods for determining the number of records in a table?
Answer:SELECT * FROM table_Name;
SELECT COUNT(*) FROM table_Name;
SELECT rows FROM indexes WHERE id = OBJECT_ID(tableName) AND indid&amp;lt; 2;
What exactly is collation?
Answer: Collation is used to specify the order of sorting in a table. Sort order can be classified into three types: Case sensitive Case Insensitive BinaryHow are global temporary tables represented, and what is their scope?
Answer: Global temporary tables are denoted by the symbol ## before the table name. Scope will be outside the session, whereas local temporary tables will be inside. @@SPID can be used to find the session ID.What is the difference between UNION and UNION ALL?
Answer: UNION: The UNION command is used to select related information from two tables. It is comparable to the JOIN command. UNION All: The UNION ALL command is equal to the UNION command, except that UNION ALL selects all values. Instead of removing duplicate rows, it will retrieve all rows from all tables.SQL Server runs on which TCP/IP port?
Answer: SQL Server runs on port 1433 by default. We can make the server listen on a specific port. This can be accomplished by modifying the TCP/IP properties in SQL Server’s configuration-box.Can we rename a column in the SQL query output?
Answer: Yes, we can do this by using the following syntax.SELECT column_name AS new_name FROM table_name;
What exactly is RDBMS?
Answer: Relational Database Management Systems, or RDBMS, are database management systems that store data in the form of tables. We can establish connections between the tables. An RDBMS can recombine data items from different files, providing powerful data-usage tools.What are SQL Server Magic Tables?
Answer: SQL Server creates magic tables to hold the values during DML operations such as Insert, Delete, and Update. These magic tables are used for data transactions within triggers.What exactly is log shipping?
Answer: Log shipping is simply the automation of database backup and restoration from one server to another standalone standby server. One of the disaster recovery solutions is this. If one server fails for any reason, the same data will be available on the backup server.In SQL Server, what is the difference between SUBSTR and CHARINDEX?
Answer: The SUBSTR function returns a specific portion of a string within a given string. However, the CHARINDEX function returns the character position in a given string.SUBSTRING('Smiley',1,3)
Gives result as Smi
CHARINDEX('i', 'Smiley',1)
Gives 3 as result as I appears in 3rd position of the string
How do you make a login?
Answer: To create a login, run the following command.CREATE LOGIN MyLogin WITH PASSWORD = '123';
What exactly is the SQL Profiler?
Answer: SQL Profiler displays a graphical representation of events in a SQL Server instance for monitoring and investment purposes. We can collect and save data for later analysis. We can also use filters to capture only the data we want.Is there a distinction between primary key and unique when the NOT NULL condition is used?
Answer: There is no difference between a primary key and a unique key; however, a unique key will accept a single NULL, whereas a primary key will not accept any NULL.SQL Server user names and passwords are stored in SQL Server.
Answer: Passwords and user names are saved in sys.server principals and sys.sql logins. Passwords, on the other hand, are not stored in plain text.What is the SIGN function used for?
Answer: The SIGN function is used to determine whether a number is Positive, Negative, or Zero. This will return a value of +1, -1, or 0. The SIGN function returns the value along with the sign. SYNTAX:SIGN (number) If the number>0, then it will return +1 If the number=0, then it will return 0 If the number<0, then it will return -1
What are SQL Server’s two authentication modes?
Answer: There are two types of authentication:- Windows Mode
- Mixed Mode
Is it possible to invoke a stored procedure from within another stored procedure?
Answer: Yes, we can invoke a stored procedure from within another stored procedure. The SQL server’s recursion property is responsible for this, and these types of stored procedures are known as nested stored procedures.What exactly is a SQL Server function?
Answer: SQL includes functions. In SQL Server, a function is a collection of statements that can take input, perform a task, and return a result. SQL Server has two types of functions: Function Defined by the System: SQL Server provides these built-in, ready-to-use functions. If it requires input parameters, enter them and get the result. Example: The code below displays the minimum, maximum, and sum of the’salary’ column values from the ’employee’ table.-
SELECT MIN(salary) AS MinSalary, MAX(salary) AS MaxSalary, SUM(salary) AS TotalSalary FROM employee
- User Defined Function:These are the functions that are written by users.
CREATE FUNCTION getAverageSalary(@salary int) RETURNS int AS BEGIN RETURN(SELECT @salary) END
What exactly is a recursive stored procedure?
Answer: SQL Server supports recursive stored procedures that call themselves. A recursive stored procedure is a method of problem solving in which the solution is arrived at repeatedly. It has a maximum nesting depth of 32 levels.CREATE PROCEDURE [dbo].[Fact] ( @Number Integer, @RetVal Integer OUTPUT ) AS DECLARE @In Integer DECLARE @Out Integer IF @Number != 1 BEGIN SELECT @In = @Number – 1 EXEC Fact @In, @Out OUTPUT - Same stored procedure has been called again(Recursively) SELECT @RetVal = @Number * @Out END ELSE BEGIN SELECT @RetVal = 1 END RETURN GO
What is the function FLOOR for?
Answer: To round up a non-integer value to the previous least integer, use the FLOOR function. An example is provided.FLOOR(6.7)Returns 6.
What exactly is the PRIMARY KEY?
Answer: A primary key column is one whose values uniquely identify each row in a table. Primary key values are never reusable.What exactly is the distinction between GETDATE and SYSDATETIME?
Answer: Both are the same, but GETDATE can provide time down to milliseconds and SYSDATETIME can provide precision down to nanoseconds. GETDATE is less accurate than SYSDATE TIME.What are the various backup types available in SQL Server?
Answer: Assume your server is up and running. Your application is gaining popularity across the internet. Then, due to a short circuit, your servers caught fire. All of the data has vanished, and there is nothing to show for it. Scary? It ought to be. This is why we should always back up our data. So that no data is lost in the event of a disaster such as hardware or software failure.
What SQL server table stores the stored procedure scripts?
Answer: Sys.SQL Modules is a SQL Server table that stores stored procedure scripts. The name of the stored procedure is saved in the Sys.Procedures table.How would you describe the creation and execution of a user-defined function in SQL Server?
Answer: The following is how to create a User-Defined function:This function can be executed as follows:CREATEFunctionfun1(@numint)returnstableasreturnSELECT*fromemployeeWHEREempid=@num;
SELECT * from fun1(12);
What are the benefits of Mirroring?
Answer: Mirroring has the following advantages: It is stronger and more efficient than log shipping. It is equipped with an automatic failover mechanism. The secondary server is in near-real-time sync with the primary.How do we determine the number of records in a table?
Answer: The following queries can be used to determine the number of records in a table:Select * from <tablename> Select count(*) from <tablename> Select rows from sysindexes where id=OBJECT_ID(tablename) and indid<2
What exactly is FOREIGN KEY?
Answer: When the primary key field of one table is added to related tables to create the common field that connects the two tables, this is referred to as a foreign key in other tables. Foreign Key constraints ensure referential consistency.What exactly is Filtered Index?
Answer: Filtered indexes are used to filter a subset of rows in a table in order to improve query performance, index maintenance, and index storage costs. When an index is created with the WHERE clause, it is referred to as a Filtered Index. These interview questions will also come in handy during your viva (orals)What are the different types of sub queries?
Answer: There are three kinds of subqueries: A single row subquery that returns a single row Subquery with multiple rows that returns multiple rows Subquery with multiple columns that returns multiple columns to the main query. The main query will be executed based on the results of the subquery.Can we check for locks in the database? If that’s the case, how can we perform this lock check?
Answer: Yes, we can examine database locks. It is possible to accomplish this by utilizing the built-in stored procedure sp lock.What exactly is normalization?
Answer: Normalization is the process of designing tables to reduce data redundancy. A database must be divided into two or more tables, with relationships defined between them. Normalization typically entails partitioning a database into two or more tables and defining relationships between them.What are SQL Server scheduled tasks?
Answer: Scheduled tasks or jobs are used to automate processes that can be run on a regular basis at a predetermined time. This task scheduling helps to reduce human intervention during the night, and feeding can be done at a specific time. The user can also specify which tasks should be generated.In SQL Server Programming, how are exceptions handled?
Answer: Exceptions are handled with TRY—-CATCH constructs, with scripts written inside the TRY block and error handling in the CATCH block.What exactly is a SQL server agent?
Answer: The SQL Server agent is essential in the day-to-day operations of a SQL server administrator (DBA). The server agent’s purpose is to easily implement tasks with the scheduler engine, allowing our jobs to run at the scheduled date and time.Can SQL servers communicate with other servers?
Answer: SQL server can connect to any database that has an OLE-DB provider to provide a link. For example, Oracle has an OLE-DB provider that connects to the SQL server group.What exactly is SQL injection?
Answer: SQL injection is a malicious user attack in which malicious code is inserted into strings that are then passed to a SQL server instance for parsing and execution. As it executes all syntactically valid queries that it receives, all statements must be checked for vulnerabilities. Skilled and experienced attackers can even manipulate parameters.What exactly is log shipping?
Answer: Log shipping is a process that automates the backup of transaction log files. We replicate the files from the primary database server to the secondary (standby) database server. You must have sysadmin privileges on the server to configure the log shipping process. Log shipping aids in disaster risk reduction. We can use the secondary server in the event of a disaster, such as a production server failure.How do I delete duplicate SQL Server rows?
Answer: SQL Server’s CTE and ROW NUMER features can be used to delete duplicate rows.What is a subquery and what are its properties?
Answer: A sub-query is a query that can be nested within another query, such as a Select, Update, Insert, or Delete statement. This can be used when free expression is permitted. Sub query properties can be defined as follows: An order by clause should not be used in a sub-query. A sub-query should be placed to the right of the main query’s comparison operator. A sub-query should be surrounded by parenthesis because it must be executed before the main query. There can be more than one sub-query.What does the SET NOCOUNT ON/OFF statement do?
Answer: NOCOUNT is set to OFF by default, and it returns the number of records affected whenever the command is executed. If the user does not want the number of records affected to be displayed, it can be explicitly set to ON- (SET NOCOUNT ON).What exactly is the UPDATE STATISTICS command?
Answer: When there are a large number of deletions, modifications, or bulk copies in indexes, the UPDATE STATISTICS command is used to update the indexes on the tables.What is the command used to get the version of SQL Server?
Answer: Select SERVERPROPERTY('productversion')
is used to get the version of SQL Server.
What exactly is a Trigger?
Answer: When insert, update, or delete commands are issued against a table, triggers are used to execute a batch of SQL code. When data is modified, triggers are automatically triggered or executed. It can be run automatically when inserting, deleting, or updating data.What is a Trigger and what are the different types of Triggers?
Answer: When a tabled event occurs, the trigger allows us to execute a batch of SQL code (INSERT, UPDATE or DELETE command executed against a specific table). DBMS is used to store and manage triggers. It is also capable of running a stored procedure. There are three types of triggers available in SQL Server: DML Triggers: DML or Data Manipulation Language triggers are called whenever a DML command, such as INSERT, DELETE, or UPDATE, is performed on a table or view. DDL Triggers: DDL or Data Definition Language triggers are triggered whenever any changes are made to the definition of any database object rather than actual data. These are extremely useful for controlling the creation and development of database environments. Logon Triggers: These are very specific triggers that fire when the SQL Server logon event occurs. This is executed prior to the establishment of a user session in the SQL Server.What query will be used to get a list of triggers in a database?
Answer: Query to get a list of database triggers-Select * from sys.objects where type='tr'
What is the SIGN function used for?
Answer: The SIGN function is used to determine whether a number is Positive, Negative, or Zero. This will return a value of +1, -1, or 0. Example –SIGN(-35) returns -1
Which command is used for custom error messages?
Answer: RAISEERROR is the command that generates and starts error processing for a specific session. These user-defined messages are saved in the table sys.messages.What are the commands UNION, MINUS, and INTERSECT?
Answer: The UNION operator joins the results of two tables while removing duplicate entries. The MINUS operator returns rows from the first query but not from the second. To combine the results of both queries into a single row, use the INTERSECT operator. Certain conditions must be met before running either of the preceding SQL statements: Each SELECT query within the clause must have the same number of columns. The column data types must also be comparable. The columns in each SELECT statement must be in the same order.What methods are used to defend against SQL injection attacks?
Answer: The methods used to protect against SQL injection attacks are as follows: For Stored Procedures, use Parameters. Input parameter filtering With Dynamic SQL, use parameter collection. User escape characters are used in the like clause.What exactly is the CDC?
Answer: CDC stands for Change Data Capture, and it is used to capture data that has recently been changed. SQL Server 2008 includes this feature.What is the distinction between OLTP and OLAP?
Answer: OLTP is an abbreviation for online transaction processing, whereas OLAP is an abbreviation for online analytical processing. OLTP stands for online database modification, whereas OLAP stands for online database query response.When should you use the UPDATE STATISTICS command?
Answer: The UPDATE STATISTICS command, as the name suggests, updates the statistics used by the index to facilitate searching.What exactly is PostgreSQL?
Answer: PostgreSQL was created in 1986 by a team led by Computer Science Professor Michael Stonebraker under the name Postgres. It was designed to help developers create enterprise-level applications by ensuring data integrity and fault tolerance in systems. PostgreSQL is an open-source, object-relational database management system that supports variable workloads and concurrent users at the enterprise level. It has always had the support of the international developer community. Because of its fault-tolerant characteristics, PostgreSQL has gained significant popularity among developers. It’s a very dependable database management system that owes its high levels of resiliency, integrity, and accuracy to more than two decades of community work. PostgreSQL is used as the primary data storage or data warehouse in many online, mobile, geospatial, and analytics applications.What exactly is TABLESAMPLE?
Answer: TABLESAMPLE is used to extract a random sample of rows that are all required for the application. The sample rows chosen are determined by the percentage of rows.What exactly is an XML Datatype?
The SQL Server database stores XML documents using the XML data type. Columns and variables are created, and XML instances are stored in the database.In insert statements, what is an IDENTITY column?
Answer: In table columns, the IDENTITY column is used to make that column an auto incremental number or a surrogate key.What exactly is SQL Bulkcopy?
Answer: Bulkcopy is a utility for copying large amounts of data from Tables. This tool is used to populate SQL Server with large amounts of data.What are the various types of Triggers?
Answer: Triggers are classified into four types: Insert Delete Update in place ofWhat exactly is View?
Answer: A view is a virtual table that contains information from multiple tables. Views limit table data access by selecting only required values and simplifying complex queries. Rows that are updated or deleted in the view are also updated or deleted in the table from which the view was created. It should also be noted that as the data in the original table changes, so does the data in the view, because views are a way to look at a subset of the original table. The results of using a view are not saved in the database indefinitely.How can data be copied from one table to another?
Answer:INSERT INTO SELECT
This command is used to insert data into a previously created table.
SELECT INTO
This command is used to create a new table and copy the structure and data from an existing table.
