Delete, Drop and Truncate

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What is the difference between Delete and Truncate commands.
Delete and truncate both commands can be used to delete data of the table.

e.g:
//Truncate Query
TRUNCATE TABLE table_name;

//Delete Query
DELETE FROM table_name WHERE < condition > ;

Difference

• Delete is a DML(Data Manipulation Language) command and is used when we specify the row(tuple) that we want to remove or delete from the table or relation. Where as Truncate is a DDL(Data Definition Language) command and is used to delete all the rows or tuples from a table.  In short Delete is used to delete specific data and Truncate is used to delete the entire data of the table. 
• We can use with where clause with Delete, but we cannot use where clause with Truncate.
• Delete locks the table row before deleting the row. The Truncate locks the entire table. 
• We can rollback the changes after executing Delete command, however we can’t rollback the changes after Truncate.
• Delete is slower than truncate 

Explain Drop command.
Drop is a Data Definition Language Command (DDL), which is used to drop the whole table. With the help of this command we can drop the whole structure in one go.

-K Himaanshu Shuklaa..