使用MySQL在表的最后一行显示总和？
要在表的最后一行显示总和，可以使用UNION。要了解如何操作，让我们创建一个表
mysql> create table showSumInLastRowDemo -> ( -> StudentId int NOT NULL AUTO_INCREMENT PRIMARY KEY, -> StudentName varchar(20), -> StudentMarks int -> );
使用insert命令在表中插入一些记录。查询如下-
mysql> insert into showSumInLastRowDemo(StudentName,StudentMarks) values('John',56);
mysql> insert into showSumInLastRowDemo(StudentName,StudentMarks) values('John',87);
mysql> insert into showSumInLastRowDemo(StudentName,StudentMarks) values('John',52);
mysql> insert into showSumInLastRowDemo(StudentName,StudentMarks) values('Carol',97);
mysql> insert into showSumInLastRowDemo(StudentName,StudentMarks) values('Larry',75);
mysql> insert into showSumInLastRowDemo(StudentName,StudentMarks) values('Larry',98);
mysql> insert into showSumInLastRowDemo(StudentName,StudentMarks) values('Carol',73);使用select语句显示表中的所有记录。查询如下-
mysql> select *from showSumInLastRowDemo;
以下是输出
+-----------+-------------+--------------+ | StudentId | StudentName | StudentMarks | +-----------+-------------+--------------+ | 1 | John | 56 | | 2 | John | 87 | | 3 | John | 52 | | 4 | Carol | 97 | | 5 | Larry | 75 | | 6 | Larry | 98 | | 7 | Carol | 73 | +-----------+-------------+--------------+ 7 rows in set (0.00 sec)
这是使用MySQL在表的最后一行显示总和的查询
mysql> (select StudentName,StudentMarks from showSumInLastRowDemo) -> UNION -> (select 'TotalMarksOfAllStudent' as StudentName,sum(StudentMarks) StudentMarks from showSumInLastRowDemo);
以下是输出
+------------------------+--------------+ | StudentName | StudentMarks | +------------------------+--------------+ | John | 56 | | John | 87 | | John | 52 | | Carol | 97 | | Larry | 75 | | Larry | 98 | | Carol | 73 | | TotalMarksOfAllStudent | 538 | +------------------------+--------------+ 8 rows in set (0.00 sec)