Question

I have a table A with columns Aname , Work

create table A(Aname varchar(40) , Work varchar(40) )

The table already has the below data inserted:

INSERT INTO A VALUES ('GREAME ','PLAYER')

Aname || Work

GREAME PLAYER

now i want that when i insert a new record, Aname–GREAME , Work—SALESMAN, then it is

inserted , but if i insert this : Aname–GREAME Work–PLAYER again, then it is not inserted

I want this:

Aname || Work

GREAME PLAYER

GREAME PLAYER — COULD NOT BE INSERTED

GREAME SALESMAN — COULD BE INSERTED

That is , the Work column checks for uniqueness when the to be inserted value of Aname

already exists.

How do i implement this? Please help with code.

EDIT——

in the insert query, the Aname column would be picked up from another table B
then how do i do it?

Answer 1

A unique constraint or a primary key will prevent you from insert with an error/exception. This insert will just not insert the row it it already exists.

insert into A (Aname, Work)
select 'GREAME', 'PLAYER'
where not exists (select *
                  from A
                  where Aname = 'GREAME' and Work = 'PLAYER')