在mysql中，可以利用聚合函數sum()對列中的元素進行求和，該函數的作用就是返回指定列的總和，語法為“SELECT SUM(列名1) AS 列名1,SUM(列名2) AS 列名2 ... FROM 表名;”。
本教程操作環境：windows10系統、mysql8.0.22版本、Dell G3電腦。
使用聚合函數sum()對MySQL中列的元素求和。語法如下-
select sum(yourColumnName1) as anyVariableName1,sum(yourColumnName2) as anyVariableName2,sum(yourColumnName3) as anyVariableName3,............N from yourTableName;
為了理解上述語法，讓我們創建一個表。以下是創建表的查詢-
mysql> create table SumDemoOnColumns
−> (
−> First int,
−> Second int,
−> Third int
−> );
使用insert命令在表中插入一些數據。查詢如下-
mysql> insert into SumDemoOnColumns values(10,20,30);
mysql> insert into SumDemoOnColumns values(40,50,60);
mysql> insert into SumDemoOnColumns values(70,80,90);
mysql> insert into SumDemoOnColumns values(100,110,120);
使用select語句顯示表中的所有記錄。查詢如下-
mysql> select *from SumDemoOnColumns;
以下是輸出-
以下是獲取列總和的查詢-
mysql> select sum(First) as First,sum(Second) as Second,sum(Third) as Third from SumDemoOnColumns;
