Question

我需要从一个表（这是一个CRM库存）到另外四个表（它们是webserver库存）进行比较。目前我正在使用以下查询，但我得到重复和误报，因为它是重新检查第一个表对着彼此的表，只是每次输出结果然后一起显示它们：

SELECT sc.Client,
       ws.[Host Header],
       ws.[IP Address],
       ws.[Status]
FROM   sc
       FULL JOIN ws
              ON sc.Urls = ws.[Host Header]
WHERE  sc.Client IS NULL
        OR ws.[Host Header] IS NULL
        OR sc.Urls <> ws.[Host Header]
UNION
SELECT sc.Client,
       ws2.[Host Header],
       ws2.[IP Address],
       ws2.[Status]
FROM   sc
       FULL JOIN ws2
              ON sc.Urls = ws2.[Host Header]
WHERE  sc.Client IS NULL
        OR ws2.[Host Header] IS NULL
        OR sc.Urls <> ws2.[Host Header]
UNION
SELECT sc.Client,
       ws3.[Host Header],
       ws3.[IP Address],
       ws3.[Status]
FROM   sc
       FULL JOIN ws3
              ON sc.Urls = ws3.[Host Header]
WHERE  sc.Client IS NULL
        OR ws3.[Host Header] IS NULL
        OR sc.Urls <> ws3.[Host Header]
UNION
SELECT sc.Client,
       ws4.[Host Header],
       ws4.[IP Address],
       ws4.[Status]
FROM   sc
       FULL JOIN ws4
              ON sc.Urls = ws4.[Host Header]
WHERE  sc.Client IS NULL
        OR ws4.[Host Header] IS NULL
        OR sc.Urls <> ws4.[Host Header]

有人能指出我正确的方向吗？我想只返回sc.Client和ws。[Host Header]字段中每个表为null或不匹配的表的不同结果，并且4个webserver表之间没有重复。

谢谢！

Answer 1

为什么不首先尝试在所有ws表之间执行UNION，然后针对UNION操作产生的表表达式执行sc表的FULL JOIN？ - Giorgos Betsos

这已经死了！我将查询调整为以下内容，一切都很顺利！

SELECT sc.Client, ws.[Host Header], ws.[IP Address], ws.[Status]
FROM sc full outer join (select * from ws1 union all select * from ws2 union all select * from ws3 union all select * from ws4) as ws ON sc.Urls = ws.[Host Header]

谢谢！

MSSQL - 将1个表中的数据与多个表进行比较

1 个答案: