我从来没有对联合查询进行过计数,并且遇到了正确完成它的问题。
我正在运行以下查询:
SELECT *
FROM
(
SELECT vg.vertrekluchthaven AS code, count(*) as countv
FROM tbl_vluchtgegevens vg
WHERE vg.vertrekdatum2 <=NOW()
GROUP BY vg.vertrekluchthaven
UNION
SELECT vg.aankomstluchthaven AS code, count(*) as counta
FROM tbl_vluchtgegevens vg
WHERE vg.vertrekdatum2 <=NOW()
GROUP BY vg.aankomstluchthaven
) vg
INNER JOIN tbl_luchthaven lh
ON lh.luchthavenID = vg.code
GROUP BY vg.code
ORDER BY lh.luchthavencode;
最终,我想弄清楚如何计算每个联合查询中的每个代码。当我运行代码时,我得到了 countv 的计数,但我没有得到任何类型的 counta。
这就是我正在寻找的:
+-------+-----------+-----------+-----------+
| CODE | Name | count v | count a |
+-------+-----------+-----------+-----------+
| AMS | LONG NAME | 5 | 8 |
| MSP | LONG NAME | 5 | 2 |
| WAS | LONG NAME | 2 | 0 |
+-------+-----------+-----------+-----------+