SQL连接问题

我有两张桌子

tblparents
----------
parentid
husbandid
wifeid 

tblnode
-------
nodeid
personid
parentid

我想要的是一个SQL语句，它获取parentid、hurst/wifeid以及parentid相等的tblnode中的行数

代码是我写的

SELECT t.parentid, t.spouseid, t.active, c.count FROM    
(SELECT parentid, wifeid spouseid from tblparents WHERE husbandid=1
UNION
SELECT parentid, husbandid spouseid from tblparents WHERE wifeid=1) t 
INNER JOIN 
(SELECT COUNT(*) count FROM tblnodes WHERE tblnodes.parentid=t.parentid) c;

它在“where子句”中给出了一个错误1054-未知列“t.parentid”

有什么办法解决吗

非常感谢，

试试这个：

SELECT t.parentid, t.spouseid, t.active, COALESCE(c.count, 0) AS count
FROM (
    SELECT parentid, wifeid spouseid
    FROM tblparents
    WHERE husbandid = 1

    UNION

    SELECT parentid, husbandid spouseid
    FROM tblparents
    WHERE wifeid = 1
) t
LEFT JOIN (
    SELECT parentid, COUNT(*) count
    FROM tblnodes
    GROUP BY parentid
) c
    ON c.parentid = t.parentid

SELECT t.parentid, t.spouseid, t.active, c.count FROM    
(SELECT parentid, wifeid spouseid from tblparents WHERE husbandid=1
UNION
SELECT parentid, husbandid spouseid from tblparents WHERE wifeid=1) t 
INNER JOIN 
(SELECT parentid, COUNT(*) count
 FROM tblnodes GROUP BY parentid) c
ON c.parentid=t.parentid) c ;

---

如果我正确理解你的问题：

SELECT t.parentid, t.husbandid, t.wifeid, COUNT(*)
LEFT JOIN tblnode n
    ON n.parentid = t.parentid
GROUP BY t.parentid. t.husbandid, t.wifeid

---

编辑：这将返回最小计数1。

出现语法错误。试试这个：

SELECT t.parentid, t.spouseid, t.active, c.count FROM    
(SELECT parentid, wifeid spouseid from tblparents WHERE husbandid=1
UNION
SELECT parentid, husbandid spouseid from tblparents WHERE wifeid=1) t 
INNER JOIN 
(SELECT parentid, COUNT(*) count
 FROM tblnodes GROUP BY parentid) c
ON c.parentid=t.parentid) c ;

但是，以下查询将执行得更好：

SELECT t.parentid, t.wifeid spouseid, t.active, COUNT(t.parentid) CNT
FROM tblparents t LEFT JOIN tblnode c
    ON t.parentid = c.parentid
GROUP BY t.parentid. t.wifeid, t.active

---

我认为在final语句中没有识别表别名t。您需要为unioned语句返回的set分配一个别名，并在select count*语句中引用该别名

这起作用了，现在又出现了另一个问题。如果count为0，则不会将其显示为行。即使计数为0，我也希望它显示该行。这非常有效，谢谢Cybernate选择t.parentid，t.wifeid-spoutseId，t.active，COUNTc.personid-CNT从tblparents t LEFT在t.parentid=c.parentid上加入tblnodes c，其中t.husbandid=1组BY t.parentid，t.wifeid