Sql SUM忽略WHERE，而不是GROUP BY

我有两个表，

adverts

和

advertsitems

。这些表具有一对多（

advertsitems

）关系。我正在动态构建这个查询，因此我使用

WHERE 1=1

来更容易地添加新条件

我有以下疑问

  SELECT a.title AS adtitle, 
         a.id AS adid, 
         a.price, 
         a.image AS image, 
         a.description, 
         SUM(ai.quantity) as quantity, 
         a.shipping, 
         a.customs, 
         a.createdate
    FROM adverts a
           LEFT JOIN advertsitems ai 
                     ON a.id = ai.advertid
   WHERE 1=1 
     AND ai.country LIKE '%AF%'
GROUP BY a.id
ORDER BY a.id DESC

---

在这种情况下，

SUM（ai.quantity）

的结果是2。如果我删除

WHERE

条件

ai.country LIKE

，结果是6。我想在两个单独的列中检索这两个值。因此，基本上我需要一个

和

，它忽略

WHERE

，而不是

GROUP BY

，使用条件聚合：

SELECT a.title AS adtitle, a.id AS adid, a.price, a.image AS image, a.description,
       SUM(ai.quantity) as totalquantity,
       SUM(case when ai.country LIKE '%AF%' then quantity else 0 end) as AFquantity
      a.shipping, a.customs, a.createdate, ai.country
FROM adverts a LEFT JOIN
     advertsitems ai
     ON a.id = ai.advertid
WHERE 1=1
GROUP BY a.id
ORDER BY a.id DESC

SELECT a.title AS adtitle, a.id AS adid, a.price, a.image AS image, a.description,
       SUM(ai.quantity) as totalquantity,
       SUM(case when ai.country LIKE '%AF%' then quantity else 0 end) as AFquantity
      a.shipping, a.customs, a.createdate
FROM adverts a LEFT JOIN
     advertsitems ai
     ON a.id = ai.advertid
WHERE 1=1 
GROUP BY a.id
HAVING ai.country LIKE '%AF%'
ORDER BY a.id DESC

如果确实要按国家筛选，请使用

having

子句。它将在聚合后进行过滤：

SELECT a.title AS adtitle, a.id AS adid, a.price, a.image AS image, a.description,
       SUM(ai.quantity) as totalquantity,
       SUM(case when ai.country LIKE '%AF%' then quantity else 0 end) as AFquantity
      a.shipping, a.customs, a.createdate, ai.country
FROM adverts a LEFT JOIN
     advertsitems ai
     ON a.id = ai.advertid
WHERE 1=1
GROUP BY a.id
ORDER BY a.id DESC

SELECT a.title AS adtitle, a.id AS adid, a.price, a.image AS image, a.description,
       SUM(ai.quantity) as totalquantity,
       SUM(case when ai.country LIKE '%AF%' then quantity else 0 end) as AFquantity
      a.shipping, a.customs, a.createdate
FROM adverts a LEFT JOIN
     advertsitems ai
     ON a.id = ai.advertid
WHERE 1=1 
GROUP BY a.id
HAVING ai.country LIKE '%AF%'
ORDER BY a.id DESC

---

嘿，再次感谢你（快速）的回复。如果我运行你的查询，我会得到广告上的所有结果，但我只想要与“ai.country-LIKE”匹配的广告。如果我在查询中添加'ai.country LIKE'，我会得到相同的结果，colums totalquantity和afquantity都是2。谢谢！你真是个天才：D我只需要在SELECT-else中添加ai.country，我就可以得到“having子句中的未知列”。