Question

我正在尝试从单个表生成数据，该表创建一个报告，显示上一个时间段（@dt）中位置a，b，c的次数。

我可以使单个SELECT查询工作，但无法弄清楚如何将它们组合在一起并生成完整的报告。错误是1241：操作数应该包含1列，我花了一个小时处理以前的答案，但我完全陷入困境。

SELECT (
SELECT DISTINCT pid, SUM(location like '%a%') FROM db.t WHERE (date > @dt) GROUP BY pid)
 AS 'a', (
SELECT DISTINCT pid, SUM(location like '%b%') FROM db.t WHERE (date > @dt) GROUP BY pid)
 AS 'b', (
SELECT DISTINCT pid, SUM(location like '%c%') FROM db.t WHERE (date > @dt) GROUP BY pid)
 AS 'c';

Answer 1

您是否在寻找每pid的点数？如果是这样，这是一个更简单的查询：

 SELECT pid, SUM(location like '%a%') as As,
        SUM(location like '%b%') as Bs,
        SUM(location like '%c%') as Cs
 FROM db.t
 WHERE (date > @dt)
 GROUP BY pid

mysql COUNT DISTINCT多列与WHERE

1 个答案: