mysql中where子句的大小写或If条件导致SQL语法中的＃1064错误

Question

My mysql query is:

SET @PID = 0
SELECT * FROM ProductMaster 
WHERE
CASE WHEN @PID = 0 THEN ID = ID ELSE ID = @PID END;

I even tried

SET @PID = 0
SELECT * FROM ProductMaster 
WHERE
IF(@PID=0, ID=ID, ID=@PID);

generates same #1064 synatx error

Answer 1

You can't use a CASE expression like that, but you may rephrase your logic as follows:

SELECT *
FROM ProductMaster
WHERE
    @PID = 0 OR ID = @PID;

Demo