- What is difference between drop and delete?
- How do you permanently delete a table in SQL?
- Why use truncate instead of delete?
- Does drop table delete the table?
- How do you delete duplicate rows in SQL?
- Does truncate free space?
- How do you drop a database?
- What happens when you drop a table in SQL?
- Does dropping a database delete it?
- Is truncate faster than delete?
- How can I delete all rows in a table without removing the table structure attributes and indexes?
- Why drop table if exists?
- What is the SQL query to delete all rows in a table without deleting the table?
- How do I remove a null row in SQL query?
- Can we rollback truncate?
What is difference between drop and delete?
DELETE is a Data Manipulation Language command, DML command and is used to remove tuples/records from a relation/table.
Whereas DROP is a Data Definition Language, DDL command and is used to remove named elements of schema like relations/table, constraints or entire schema.
DROP is DDL..
How do you permanently delete a table in SQL?
Using SQL Server Management StudioIn Object Explorer, select the table you want to delete.Right-click the table and choose Delete from the shortcut menu.A message box prompts you to confirm the deletion. Click Yes. Deleting a table automatically removes any relationships to it.
Why use truncate instead of delete?
Truncate removes all records and doesn’t fire triggers. Truncate is faster compared to delete as it makes less use of the transaction log. Truncate is not possible when a table is referenced by a Foreign Key or tables are used in replication or with indexed views.
Does drop table delete the table?
drop table is different from deleting all of the records in the table. Deleting all of the records in the table leaves the table including column and constraint information. Dropping the table removes the table definition as well as all of its rows.
How do you delete duplicate rows in SQL?
To delete the duplicate rows from the table in SQL Server, you follow these steps:Find duplicate rows using GROUP BY clause or ROW_NUMBER() function.Use DELETE statement to remove the duplicate rows.
Does truncate free space?
If you’re using innodb_file_per_table=ON, or you’re using MyISAM, TRUNCATE TABLE will delete the table files used by the table in question (and create new, empty ones). So, the space used will be released to the file system, and in Unix/Linux, “df” on the file system will show new space.
How do you drop a database?
Using the SQL Server DROP DATABASE statement to delete a database. To remove an existing database from a SQL Server instance, you use the DROP DATABASE statement. In this syntax, you specify the name of the database that you want to drop after the DROP DATABASE keywords.
What happens when you drop a table in SQL?
We use the SQL DROP Table command to drop a table from the database. It completely removes the table structure and associated indexes, statistics, permissions, triggers and constraints. You might have SQL Views and Stored procedures referencing to the SQL table.
Does dropping a database delete it?
DROP DATABASE drops all tables in the database and deletes the database. Be very careful with this statement! To use DROP DATABASE, you need the DROP privilege on the database. DROP SCHEMA is a synonym for DROP DATABASE .
Is truncate faster than delete?
TRUNCATE removes all rows from a table. The operation cannot be rolled back and no triggers will be fired. As such, TRUNCATE is faster and doesn’t use as much undo space as a DELETE.
How can I delete all rows in a table without removing the table structure attributes and indexes?
DELETE statement Syntax DELETE FROM table_name WHERE Condition; To remove all the rows from the table: DELETE FROM table_name; This statement removes all the records from table but the table itself is not deleted, thus table structure, attributes and indexes remains intact.
Why drop table if exists?
The DROP TABLE SQL statement enables you to delete a table from the database. If the table did not exist then attempting to DROP it would cause an error to occur. The DROP TABLE IF EXISTS SQL statement enables a check to see that the table exists prior to attempting the dropping (deletion) of the table.
What is the SQL query to delete all rows in a table without deleting the table?
To delete every row in a table:Use the DELETE statement without specifying a WHERE clause. With segmented table spaces, deleting all rows of a table is very fast. … Use the TRUNCATE statement. The TRUNCATE statement can provide the following advantages over a DELETE statement: … Use the DROP TABLE statement.
How do I remove a null row in SQL query?
Use the delete command to delete blank rows in MySQL. delete from yourTableName where yourColumnName=’ ‘ OR yourColumnName IS NULL; The above syntax will delete blank rows as well as NULL row.
Can we rollback truncate?
When you execute a Truncate statement, it does not get logged in the log file as it is a DDL statement. So if you Truncate a table, you cannot Roll Back to a point in time before the truncate. However, in a Transaction, Rollback is permitted and functions just as any other rollback would.