MySQL 选择累计(运行总和)列?

mysqlmysqli database

要选择累计列,我们首先创建一个演示表。创建表的查询如下 −

mysql> create table accumulatedDemo
   -> (
   -> Value int
   -> );
Query OK, 0 rows affected (0.58 sec)

使用 insert 命令在表中插入一些记录。 查询语句如下 −

mysql> insert into accumulatedDemo values(10);
Query OK, 1 row affected (0.21 sec)
mysql> insert into accumulatedDemo values(15);
Query OK, 1 row affected (0.09 sec)
mysql> insert into accumulatedDemo values(20);
Query OK, 1 row affected (0.13 sec)
mysql> insert into accumulatedDemo values(25);
Query OK, 1 row affected (0.12 sec)
mysql> insert into accumulatedDemo values(45);
Query OK, 1 row affected (0.14 sec)

使用 select 语句显示表中的所有记录。查询如下 −

mysql> select *from accumulatedDemo;

这是输出 −

+-------+
| Value |
+-------+
| 10    |
| 15    |
| 20    |
| 25    |
| 45    |
+-------+
5 rows in set (0.00 sec)

以下是选择累积列的查询 −

mysql> set @previousSum =0;
Query OK, 0 rows affected (0.00 sec)
mysql> select Value, @previousSum: =@previousSum+ Value AS AccumulatedColumn from accumulatedDemo;

这是输出 −

+-------+-------------------+
| Value | AccumulatedColumn |
+-------+-------------------+
| 10    | 10                |
| 15    | 25                |
| 20    | 45                |
| 25    | 70                |
| 45    | 115               |
+-------+-------------------+
5 rows in set (0.00 sec)

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