What is Union and UNION ALL?

UNION is used to select unique data from two tables whereas UNION ALL is used to select all data including duplicates from the tables.

What is the difference among UNION, MINUS and INTERSECT?

UNION combines the results from 2 tables and eliminates duplicate records from the result set.

MINUS operator when used between 2 tables, gives us all the rows from the first table except the rows which are present in the second table.

INTERSECT operator returns us only the matching or common rows between 2 result sets.

Why we use SQL?

We use SQL for Manipulate and Execute data.

What is a clause?

It is a command for SQL.

.
What is Drop?

Delete the whole table with table structure.

What is Deleting?

Delete the data records from a table, depending on where ‘clause’.

What is Truncate?

Delete all rows of table but the table structure remains in the database.

What is the different between Union and Join?

Union is to select related information from two tables and Join combines two or more tables to retrieve data from multiple tables.