Question

I have a SQL query, it looks like that:

insert into tableA(order_id, contractnotenumber, shipmentdate, comment) 
    values ((select entity_id from tableb where increment_id = '12345678'), 
    '', '1970-01-01', '');

Now, if the subquery ((select entity_id from tableb where increment_id = ‘12345678’)) returns null, the insert does not work. What I want is an easy way to say that if the subquery returns null, dont do anything. I tried insert ignore, but this inserts the row with 0 instead of null, which works, but its not what I want. In SQL Server I used if not exists(select…), but this does not work with MYSQL.

Ideas?

Thanks!

Answer 1

insert into tableA(order_id, contractnotenumber, shipmentdate, comment)
select entity_id, '', '1970-01-01', '' from tableb where increment_id = '12345678'

This won’t insert anything if the row isn’t found in tableb