Sql 如何将两个表连接在一起，并从两个表中解压到一列中？

这里我有两个问题：

SELECT bk, search, ckey, dn
FROM 
   (SELECT t1_bk_no AS 'bk', 
         t1_full_key AS 'ckey', 
         CAST(t1_info1 AS VARCHAR(100)) AS [1],
         CAST(t1_info2 AS VARCHAR(100)) AS [2],
         CAST(t1_info3 AS VARCHAR(100)) AS [3],
         CAST(t1_info4 AS VARCHAR(100)) AS [4],
         CAST(t1_info5 AS VARCHAR(100)) AS [5]
   FROM dbo.FirstTable) PNT
   UNPIVOT( searcg FOR dn IN ( [1],[2],[3],[4],[5] ) ) AS UPV
WHERE search NOT IN ( '0', '999999999', '') AND search IS NOT NULL

及

基本上我想加入这两个表。正在努力找到join语句的放置位置

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感谢您的帮助。

在没有看到所需结果的情况下，您似乎可以使用UNION ALL查询，因为列看起来是相同的：

SELECT bk, search, ckey, dn
FROM 
(
  SELECT t1_bk_no AS 'bk', 
         t1_full_key AS 'ckey', 
         CAST(t1_info1 AS VARCHAR(100)) AS [1],
         CAST(t1_info2 AS VARCHAR(100)) AS [2],
         CAST(t1_info3 AS VARCHAR(100)) AS [3],
         CAST(t1_info4 AS VARCHAR(100)) AS [4],
         CAST(t1_info5 AS VARCHAR(100)) AS [5]
   FROM dbo.FirstTable
) PNT
UNPIVOT( search FOR dn IN ( [1],[2],[3],[4],[5] ) ) AS UPV
WHERE search NOT IN ( '0', '999999999', '') AND search IS NOT NULL
UNION ALL
SELECT bk, search, ckey, dn
FROM 
(
   SELECT t2_bk_no AS 'bk', 
         t2_full_key AS 'ckey', 
         CAST(t2_info1 AS VARCHAR(100)) AS [6],
         CAST(t2_info2 AS VARCHAR(100)) AS [7],
         CAST(t2_info3 AS VARCHAR(100)) AS [8]
   FROM dbo.SecondTable
) PNT
UNPIVOT( search FOR dnIN ( [1],[5],[7] ) ) AS UPV
WHERE search NOT IN ( '0', '999999999', '') AND search IS NOT NULL;

---

你期望的输出是什么？仅仅是两个查询的结果的组合？如果是这样，您希望合并它们，否则，请给出一个输出示例。是的，谢谢您的帮助。这很有效，谢谢您的帮助。基本上，我在这里学到的是，只要两个表中的列之间存在匹配，JOIN语句就会选择两个表中的所有行；而UNION用于组合两个或多个SELECT语句的结果集。

SELECT bk, search, ckey, dn
FROM 
(
  SELECT t1_bk_no AS 'bk', 
         t1_full_key AS 'ckey', 
         CAST(t1_info1 AS VARCHAR(100)) AS [1],
         CAST(t1_info2 AS VARCHAR(100)) AS [2],
         CAST(t1_info3 AS VARCHAR(100)) AS [3],
         CAST(t1_info4 AS VARCHAR(100)) AS [4],
         CAST(t1_info5 AS VARCHAR(100)) AS [5]
   FROM dbo.FirstTable
) PNT
UNPIVOT( search FOR dn IN ( [1],[2],[3],[4],[5] ) ) AS UPV
WHERE search NOT IN ( '0', '999999999', '') AND search IS NOT NULL
UNION ALL
SELECT bk, search, ckey, dn
FROM 
(
   SELECT t2_bk_no AS 'bk', 
         t2_full_key AS 'ckey', 
         CAST(t2_info1 AS VARCHAR(100)) AS [6],
         CAST(t2_info2 AS VARCHAR(100)) AS [7],
         CAST(t2_info3 AS VARCHAR(100)) AS [8]
   FROM dbo.SecondTable
) PNT
UNPIVOT( search FOR dnIN ( [1],[5],[7] ) ) AS UPV
WHERE search NOT IN ( '0', '999999999', '') AND search IS NOT NULL;