MYSQL中,CAST函式的使用規則
阿新 • • 發佈:2018-12-22
CAST函式語法規則是:Cast(欄位名 as 轉換的型別 ),其中型別可以為:
SIGNED int
CHAR[(N)] 字元型
DATETIME 日期和時間型
DATE 日期型
TIME 時間型
DECIMAL float型
/*SIGNED int*/
date:2015-11-03 15:31:26
select cast(date as signed) as date from table1;
/*結果*/
date:20151103153126
select cast(date as char) as date from table1; /*結果如下:*/ date:2015-11-03 15:31:26 select cast(date as datetime) as date from table1; /*結果如下:*/ date:2015-11-03 15:31:26 select cast(date as date) as date from table1; /*結果如下:*/ date:2015-11-03 select cast(date as time) as date from table1; /*結果如下:*/ date:15:31:26 select cast(num as decimal(10, 2)) as num from table2 /*結果如下:*/ num:20.00
解釋:decimal 資料型別最多可儲存 38 個數字,所有數字都能夠放到小數點的右邊.decimal 資料型別儲存了一個準確(精確)的數字表達法;不儲存值的近似值.其中10是小數點左邊和右邊的數字個數之和(不包括小數點),2代表小數點右邊的小數位數或數字個數.decimal(10,2)可以儲存8位整數2位小數的數字.