首先创建一个拆分函数:

First, create a split function:

CREATE FUNCTION dbo.SplitStrings
(
    @List       NVARCHAR(MAX),
    @Delimiter  NVARCHAR(255)
)
RETURNS TABLE
AS
    RETURN (SELECT Number = ROW_NUMBER() OVER (ORDER BY Number),
        Item FROM (SELECT Number, Item = LTRIM(RTRIM(SUBSTRING(@List, Number, 
        CHARINDEX(@Delimiter, @List + @Delimiter, Number) - Number)))
    FROM (SELECT ROW_NUMBER() OVER (ORDER BY s1.[object_id])
        FROM sys.all_objects AS s1 CROSS APPLY sys.all_objects) AS n(Number)
    WHERE Number <= CONVERT(INT, LEN(@List))
        AND SUBSTRING(@Delimiter + @List, Number, 1) = @Delimiter
    ) AS y);
GO

现在您可以简单地推断:

Now you can extrapolate simply by:

SELECT s.[message-id], f.Item
  FROM dbo.SourceData AS s
  CROSS APPLY dbo.SplitStrings(s.[recipient-address], ';') as f;

另外我建议不要在列名中放置破折号.这意味着您必须始终将它们放在 [方括号] 中.

Also I suggest not putting dashes in column names. It means you always have to put them in [square brackets].