如何在SQL Server中连接字符串和逗号？

Question

我对MSSQL比较陌生,如果这个问题听起来很简单,那就很抱歉.我想用分隔符连接多个字段,.但是,当该字段为空时,额外的内容,也将包含在结果字符串中.那么有一个简单的方法来解决这个问题吗？例如,

SELECT VRI.Street_Number_and_Modifier + ',' + 
       VRI.Street_Direction + ',' + 
       VRI.Street_Name + ',' + 
       VRI.Street_Direction + ',' + 
       VRI.Street_Suffix + ',' + 
       VRI.Street_Post_Direction + ',' + 
       VRI.Unit
FROM View_Report_Information_Tables VRI

Answer 1

这个Lamak的修改版本处理NULL或只包含空格/空的字符串:

SELECT  COALESCE(NULLIF(VRI.Street_Number_and_Modifier, '') + ',', '') + 
        COALESCE(NULLIF(VRI.Street_Direction, '') + ',', '') + 
        COALESCE(NULLIF(VRI.Street_Name, '') + ',', '') + 
        COALESCE(NULLIF(VRI.Street_Direction, '') + ',', '') + 
        COALESCE(NULLIF(VRI.Street_Suffix, '') + ',', '') + 
        COALESCE(NULLIF(VRI.Street_Post_Direction, '') + ',', '') + 
        COALESCE(NULLIF(VRI.Unit, ''), '')
FROM View_Report_Information_Tables VRI

Answer 2

我能够通过稍微不同的方法来实现它.将逗号放在每个字段的开头,然后使用STUFF函数删除第一个字符对我有用:

SELECT 

    STUFF((COALESCE(', ' + NULLIF(VRI.Street_Number_and_Modifier, ''), '') +
        COALESCE(', ' + NULLIF(VRI.Street_Direction, ''), '') + 
        COALESCE(', ' + NULLIF(VRI.Street_Name, ''), '')) +
        COALESCE(', ' + NULLIF(VRI.Street_Direction, ''), '')) +
        COALESCE(', ' + NULLIF(VRI.Street_Suffix, ''), '')) +
        COALESCE(', ' + NULLIF(VRI.Street_Post_Direction, ''), '')) +
        COALESCE(', ' + NULLIF(VRI.Unit, ''), ''))
    , 1, 2, '')

FROM View_Report_Information_Tables AS VRI

Answer 3

如果列为空而不是null,则可以尝试以下操作:

SELECT VRI.Street_Number_and_Modifier 
    + CASE WHEN VRI.Street_Number_and_Modifier <> '' THEN ', ' ELSE '' END
       + VRI.Street_Direction
    + CASE WHEN VRI.Street_Direction <> '' THEN ', ' ELSE '' END
       + VRI.Street_Name
    + CASE WHEN VRI.Street_Name <> '' THEN ', ' ELSE '' END
       + VRI.Street_Direction
    + CASE WHEN VRI.Street_Direction <> '' THEN ', ' ELSE '' END
       + VRI.Street_Suffix
    + CASE WHEN VRI.Street_Suffix <> '' THEN ', ' ELSE '' END
       + VRI.Street_Post_Direction
    + CASE WHEN VRI.Street_Post_Direction <> '' THEN ', ' ELSE '' END
       + VRI.Unit
    + CASE WHEN VRI.Unit<> '' THEN ', ' ELSE '' END
FROM View_Report_Information_Tables VRI