Question

我试图运行类似于以下内容的查询。我基本上试图有条件地更改更新文本的格式。我需要一些帮助，因为我已经尝试了几种不同的方法而没有成功。提前谢谢。

UPDATE bL SET 
bL.[QUANTITY] = bL.[QUANTITY] + 2,
bL.[SERIAL_NUMBERS] = 
    (
      CASE WHEN bL.[SERIAL_NUMBERS] IS NOT NULL 
      THEN ISNULL(bL.[SERIAL_NUMBERS], '') + 'EOSB7U310007; EOSB7U310022' 
      ELSE bL.[SERIAL_NUMBERS] + '; EOSB7U310007; EOSB7U310022'
    ) 
 FROM [ROBOTICS_OPTICS_MECHUAT].[dbo].[AOF_BOXES_LINES] AS bL 
 LEFT JOIN [ROBOTICS_OPTICS_MECHUAT].[dbo].[AOF_BOXES] AS bO 
 ON bL.[AOF_BOXES_ID] = bO.[ID] 
 WHERE bO.[SELECTED] = 'True'

Answer 1

因此，将我发现的所有评论放在一个答案中，您的代码应该如下所示：

UPDATE bL SET 
bL.[QUANTITY] = bL.[QUANTITY] + 2,
bL.[SERIAL_NUMBERS] = 
    (
      CASE WHEN bL.[SERIAL_NUMBERS] IS NULL 
      THEN 'EOSB7U310007; EOSB7U310022' 
      ELSE bL.[SERIAL_NUMBERS] + '; EOSB7U310007; EOSB7U310022'
      END
    ) 
 FROM [ROBOTICS_OPTICS_MECHUAT].[dbo].[AOF_BOXES_LINES] AS bL 
 LEFT JOIN [ROBOTICS_OPTICS_MECHUAT].[dbo].[AOF_BOXES] AS bO 
 ON bL.[AOF_BOXES_ID] = bO.[ID] 
 AND bO.[SELECTED] = 'True'

然而它可以缩短 - 像这样：

UPDATE bL SET 
bL.[QUANTITY] = bL.[QUANTITY] + 2,
bL.[SERIAL_NUMBERS] = ISNULL(bL.[SERIAL_NUMBERS] + '; ', '') + 'EOSB7U310007; EOSB7U310022'
 FROM [ROBOTICS_OPTICS_MECHUAT].[dbo].[AOF_BOXES_LINES] AS bL 
 LEFT JOIN [ROBOTICS_OPTICS_MECHUAT].[dbo].[AOF_BOXES] AS bO 
 ON bL.[AOF_BOXES_ID] = bO.[ID] 
 AND bO.[SELECTED] = 'True'

这是因为它bL.[SERIAL_NUMBERS]的值为null，那么它与;的串联也将为空。

注意：

我已将bO.[SELECTED] = 'True'从WHERE子句移至ON子句。这是因为当使用左连接时，右表上的所有条件都应该在ON子句上，否则连接将变为内连接。
好像您正在使用bL.[SERIAL_NUMBERS]列来存储多个值。这是99.9999％的案件中的一个大错误阅读Is storing a delimited list in a database column really that bad?，您将看到很多原因。

Answer 2

您不需要SELECT，而且必须END发出CASE声明。

UPDATE  bL
SET     bL.[QUANTITY] = bL.[QUANTITY] + 2
      , bL.[SERIAL_NUMBERS] = ( CASE WHEN bL.[SERIAL_NUMBERS] IS NOT NULL 
                                     THEN ISNULL(bL.[SERIAL_NUMBERS] , '') + 'EOSB7U310007; EOSB7U310022'
                                     ELSE bL.[SERIAL_NUMBERS] + '; EOSB7U310007; EOSB7U310022'
                                END )
FROM    [ROBOTICS_OPTICS_MECHUAT].[dbo].[AOF_BOXES_LINES] AS bL
LEFT JOIN [ROBOTICS_OPTICS_MECHUAT].[dbo].[AOF_BOXES] AS bO ON bL.[AOF_BOXES_ID] = bO.[ID]
WHERE   bO.[SELECTED] = 'True';

带有子查询的SQL更新Null条件

2 个答案: