How do you write a mysql query statement-CodePudding

Home > database > How do you write a mysql query statement

How do you write a mysql query statement

Time：10-06

Question: whether the query table containing the Id if not include return Id if contain won't return

CodePudding user response:

This effect?

 set @ id=2000; 
Select count (*) into @ con from t1 where id=@ id; 
Select the if (@ con>=0, @ id, 0);

If it is stored procedures can be used if the exists of judgment

CodePudding user response:

 # 10 id for this value 
Select case when id is null then 10 else 'end from t where id=10