mysql怎么实现mssql的if exists() begin...end功能？

Answer 1

IF ELSE语句

IF EXISTS (SELECT 1 FROM dual WHERE 1=1) 
THEN
    #TODO
ELSE 
    #TODO
END IF;

IF ELSEIF ELSE 语句

IF(XXXX) THEN 
    #TODO
ELSEIF(XXXXX) THEN
    #TODO
ELSEIF(XXXX) THEN
ELSE
    #TODO
END ID;

Answer 2

已搞定，原来和mssql差不多的