MYSQL 自定義函數（if else）

IF OBJECT_ID('dbo.GetDateDiff', 'FN') IS NOT NULL OR OBJECT_ID('dbo.GetDateDiff', 'TF') IS NOT NULL OR OBJECT_ID('dbo.GetDateDiff', 'IF') IS NOT NULL DROP FUNCTION dbo.GetDateDiff     //判斷此函數是否存在，若存在，

>>阅读原文<<