MySQL 如何忽略特定记录并添加剩余的相应记录（数字）

首先，让我们创建一张表 –

mysql> create table DemoTable
   -> (
   -> Name varchar(20),
   -> Amount int
   -> );
Query OK, 0 rows affected (0.61 sec)

使用 INSERT 命令向表中插入一些记录 –

mysql> insert into DemoTable values('John',200);
Query OK, 1 row affected (0.17 sec)
mysql> insert into DemoTable values('Chris',150);
Query OK, 1 row affected (0.18 sec)
mysql> insert into DemoTable values('Mike',500);
Query OK, 1 row affected (0.19 sec)
mysql> insert into DemoTable values('John',350);
Query OK, 1 row affected (0.18 sec)

使用 SELECT 语句显示表中的所有记录 –

mysql> select * from DemoTable;

这将产生以下输出 –

+-------+--------+
| Name  | Amount |
+-------+--------+
| John  | 200    |
| Chris | 150    |
| Mike  | 500    |
| John  | 350    |
+-------+--------+
4 rows in set (0.00 sec)

以下是忽略特定记录并添加剩余记录（数字）的查询 –

mysql> select sum(Amount) from DemoTable
   -> where Name!='John';

这将产生以下输出 –

+-------------+
| sum(Amount) |
+-------------+
|          650 |
+-------------+
1 row in set (0.00 sec)

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