MySQL insert a record by checking if record exist then add
I just figured out this trick in MySQL with the INSERT ... SELECT statement functionality. How to do it, so I have a table named OFFERS and table named ACCOUNTS. Let's assumed that I have fields on these table, and it has OFFERS.CODE, OFFERS.USERID and ACCOUNTS.USERID. What I want is, I want to check if ACCOUNTS.USERID exist in OFFERS table in just one SQL statement. To do this, just do INSERT INTO OFFERS (USERID, CODE) SELECT ' 22 ',' XXHH22BBMM ' FROM ACCOUNT a WHERE A.USERID=' 22 ' AND A.USERID NOT IN ( SELECT OFFER.USERID FROM OFFER WHERE OFFER.USERID=' 22 ' ) LIMIT 1 Now, the 22 is the USERID and the XXHH22BBMM values are used as my return value that I wanted actually to be inserted into the database. What exactly is happening here is that, this is equivalent to, INS...