php - 如何连接多个表和 SUM 值？

Question

我有以下表格（和示例值）：

**table1**
data_id (1, 2)

**table2:**
data_id (1, 2, 1, 2)
month(01, 01, 02, 02)
data(10, 5, 11, 2)

**table3**
data_id (1, 2, 1, 2)
month(01, 01, 02, 02)
data(10, 5, 11, 2)

**table4**
data_id (1, 2, 1, 2)
month(01, 01, 02, 02)
data(10, 5, 11, 2)

所有表都由“data_id”连接。我需要汇总数据字段并按月分组。表结果如下所示：

**result**
month(01, 02)
table2.data(15, 13)
table3.data(15, 13)
table4.data(15, 13)

获取结果表的 SQL 语句是什么？

Answer 1

试试这个查询编辑

SELECT t2.month, sum(t2.data), sum(t3.data), sum(t4.data)
FROM table1 t1, table2 t2, table3 t3, table4 t4
WHERE t1.data_id = t2.data_id AND t1.data_id = t3.data_id AND t1.data_id = t4.data_id
AND t2.month = t3.month AND t3.month = t4.month
GROUP BY t2.month;

它按月汇总数据字段的值

小提琴