How to join the same table in sql

Question

The scenerio of query is

select * from table1 where colName = 'John' and age(select age from
 table1) <> 21

Need data with all the row names as John but their age should not be 21.

How to join the same table?

Answer 1

As other answers suggest, you don't need a self-join for this scenario. However, self joins are possible in SQL

SELECT * from table1 t1,table1 t2 where t1.id=t2.id and t1.name='John' and t2.age <> 21 

But you really shouldn't do this for your scenario.

Answer 2

Try this

select * from table1 where names = 'John' and age <> 21

You can check this link to understand how we can join multiple conditions with select query in ORACLE.