SQL Queries

Data Definition Language (DDL) statements are used to define the database structure or schema. Some examples:

• Create 
• Create Database 
• Create Table

• Alter
• Delete Column
• Add New Column

• Drop
• Delete Existing Database
• Drop Table

• Truncate
• Truncate Table

• Comment
• Comment 

• Rename 
• Table Name 
• Column Name

Data Manipulation Language (DML) statements are used for managing data within schema objects. Some examples: 

• Select 
• Column of table

• Insert
• Insert values 

• Update
• Update Values in Table

• Delete
• Delete Row

• Merge/Join 
• JOIN or INNER JOIN 
• FULL or LEFT JOIN

• Call

• Explain Plan 

• Lock Table

Data Control Language (DCL) statements. Some examples:

• GRANT - gives user's access privileges to database 

• REVOKE - withdraw access privileges given with the GRANT command

Transaction Control (TCL) statements are used to manage the changes made by DML statements. It allows statements to be grouped together into logical transactions.

• COMMIT - save work done

• SAVEPOINT - identify a point in a transaction to which you can later roll back

• ROLLBACK - restore database to original since the last COMMIT 

• SET TRANSACTION - Change transaction options like isolation level and what rollback segment to use.

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