如何使這個MySQL查詢子工作

Question

SELECT c.noreg AS noreg, count(*) AS jumlah 
FROM kamar a, reservasi b, register c, identitas_psn d, sub_unit_kamar e 
WHERE a.idkamar = b.kamar 
AND b.noreg = c.id_reg_lengkap 
AND c.norm = d.norm 
AND c.idunit = e.id_subunit 
AND c.noreg NOT 
IN (

SELECT noreg 
FROM register_keluar 
) 
AND (
c.idunit LIKE '20%' 
) 
AND jumlah > 1 
GROUP BY noreg 
ORDER BY jumlah DESC 

//錯誤是：AND jumlah> 1

Answer 1

移動jumlah > 1成HAVING條款，如：

... 
GROUP BY ... 
HAVING jumlah > 1 
ORDER BY ... 

http://en.wikipedia.org/wiki/Having_(SQL）：

SQL中的HAVING子句指定 SQL SELECT語句應該只有 返回聚合值 滿足指定條件的行。

Answer 2

嘗試：

SELECT c.noreg AS noreg, count(*) AS jumlah 
FROM kamar a, reservasi b, register c, identitas_psn d, sub_unit_kamar e 
WHERE a.idkamar = b.kamar 
AND b.noreg = c.id_reg_lengkap 
AND c.norm = d.norm 
AND c.idunit = e.id_subunit 
AND c.noreg NOT 
IN (SELECT noreg FROM register_keluar AND c.idunit LIKE '20%') 
AND jumlah > 1 
GROUP BY noreg 
ORDER BY jumlah DESC 

Answer 3

當你結合的任何列的選擇和聚合別名（在你的例子：COUNT（*）作爲jumlah），然後你打算使用該聚合別名（ jumlah）在你的查詢的某個地方，用GROUP BY的條件，你需要使用一個HAVING條件後面那個對應的GROUP BY。