Question

我有一个包含500行的表，另一个包含750行左右的表。我正在做的是，我从第二个表中获取了某一列的随机500行，并且我希望使用这500个值更新第一个表上新添加的列。

我知道如何进行如下更新：

UPDATE schema.table1
SET column = cl.column FROM schema.table1 cl
INNER JOIN table2 cf ON cf.column = cl.column

但我没有在两个表中都匹配的任何列。有没有办法在不必匹配内部联接的列的情况下执行此操作？

基本上，我想在一个表中更新500行1列，其中500个值来自另一个表

Answer 1

您可以使用ROW_NUMBER生成列来连接两个表。看一下示例和输出

DECLARE @T1 TABLE ( column1 INT ,column2 VARCHAR(2) )

DECLARE @T2 TABLE ( column1 VARCHAR(2) )

INSERT INTO @T1 ( column1, column2 ) 
        VALUES  ( 0, 'A' ), ( 1, 'B' ), ( 2, 'C' )

INSERT INTO @T2 ( column1 ) 
    VALUES ( 'D'),( 'F'),( 'G' )


SELECT *, ROW_NUMBER() OVER (PARTITION BY 1 ORDER BY (SELECT NULL) ) AS RN FROM @T1
SELECT *, ROW_NUMBER() OVER (PARTITION BY 1 ORDER BY (SELECT NULL) ) AS RN FROM @T2

;WITH CTE_1 AS (SELECT *, ROW_NUMBER() OVER (PARTITION BY 1 ORDER BY (SELECT NULL) ) AS RN FROM @T1)
    ,cte_2 AS (SELECT *, ROW_NUMBER() OVER (PARTITION BY 1 ORDER BY (SELECT NULL) ) AS RN FROM @T2)
UPDATE t1
SET t1.column2 = t2.column1
FROM CTE_1 t1
JOIN cte_2 t2
ON t1.rn = t2.rn

SELECT *, ROW_NUMBER() OVER (PARTITION BY 1 ORDER BY (SELECT NULL) ) AS RN FROM @T1
SELECT *, ROW_NUMBER() OVER (PARTITION BY 1 ORDER BY (SELECT NULL) ) AS RN FROM @T2

更新表的所有行的列

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