mysql存储过程学习

1.判断不能用"=="一律是"="

2.动态sql语句：CONCAT

SET dynamicSql = CONCAT('SELECT COUNT(ID) FROM e00_user WHERE APP_ID = ''',userId_in,''''); SET @d_sql = dynamicSql; PREPARE sign FROM @d_sql; EXECUTE sign; DEALLOCATE PREPARE sign;

3.参数不指明的情况下默认为入参，OUT/IN指明入参或出参