案例表达式只能嵌套到10级

Question

我必须处理的电话号码,如澳大利亚国家代码下面的代码+61,61,001161等我有我不能插入任何问题CASE了声明下:CASE WHEN LEFT(@BPartyNo, 4) = '+610'

它说Case表达式只能嵌套到10级

如何简化这个TSQL,以便我可以添加更多CASE？

USE [TelcoStage_PROD]
GO
/****** Object:  UserDefinedFunction [dbo].[ufn_stg_ProperBPartyNoExtra]    Script Date: 07/12/2010 15:27:52 ******/
SET ANSI_NULLS ON
GO
SET QUOTED_IDENTIFIER ON
GO

--=====================================================================================================================
-- OBJECT NAME          : dbo.ufn_stg_ProperBPartyNoExtra
-- INPUTS               : @BPartyNo 
-- OUTPUTS              : VARCHAR(32)
-- RETURN CODES         : N/A
-- DEPENDENCIES         : N/A
-- DESCRIPTION          : This function is used to get the extra after 10 character (MNET or S)
--
-- EXAMPLES (optional)  : N/A
--
-- HISTORY:
-- #-----------------------------------------------------------------------------------------------------------------
-- # DATE       | VERSION        | MODIFIED BY | DESCRIPTION
-- #-----------------------------------------------------------------------------------------------------------------
====================================================================================================================


ALTER FUNCTION [dbo].[ufn_stg_ProperBPartyNoExtra](@BPartyNo AS VARCHAR(MAX))RETURNS VARCHAR(32)
AS
BEGIN   
    DECLARE @Return VARCHAR(32);

    SET @Return = '';

    IF (LEN(@BPartyNo) > 0) 
        SELECT @Return = CASE WHEN LEFT(@BPartyNo, 4) = '+610' THEN SUBSTRING('0' + SUBSTRING(@BPartyNo, 5, LEN(@BPartyNo)), 11, LEN( '0' + SUBSTRING(@BPartyNo, 5, LEN(@BPartyNo)) ) ) ELSE
                                    CASE WHEN LEFT(@BPartyNo, 3) = '+61' THEN SUBSTRING('0' + SUBSTRING(@BPartyNo, 4, LEN(@BPartyNo)), 11, LEN( '0' + SUBSTRING(@BPartyNo, 4, LEN(@BPartyNo)) ) ) ELSE
                                        CASE WHEN LEFT(@BPartyNo, 2) = '61' THEN SUBSTRING('0' + SUBSTRING(@BPartyNo, 3, LEN(@BPartyNo)), 11, LEN( '0' + SUBSTRING(@BPartyNo, 3, LEN(@BPartyNo)) ) ) ELSE       
                                            CASE WHEN LEFT(@BPartyNo, 6) = '001161' THEN SUBSTRING('0' + SUBSTRING(@BPartyNo, 7, LEN(@BPartyNo)), 11, LEN( '0' + SUBSTRING(@BPartyNo, 7, LEN(@BPartyNo)) ) ) ELSE 
                                                CASE WHEN ( LEFT(@BPartyNo,2) = '01' AND LEN(@BPartyNo) > 10 ) THEN SUBSTRING(@BPartyNo, 11, LEN(@BPartyNo)) ELSE 
                                                    CASE WHEN ( LEFT(@BPartyNo,2) = '02' AND LEN(@BPartyNo) > 10 ) THEN SUBSTRING(@BPartyNo, 11, LEN(@BPartyNo)) ELSE 
                                                        CASE WHEN ( LEFT(@BPartyNo,2) = '03' AND LEN(@BPartyNo) > 10 ) THEN SUBSTRING(@BPartyNo, 11, LEN(@BPartyNo)) ELSE 
                                                            CASE WHEN ( LEFT(@BPartyNo,2) = '04' AND LEN(@BPartyNo) > 10 ) THEN SUBSTRING(@BPartyNo, 11, LEN(@BPartyNo)) ELSE 
                                                                CASE WHEN ( LEFT(@BPartyNo,2) = '07' AND LEN(@BPartyNo) > 10 ) THEN SUBSTRING(@BPartyNo, 11, LEN(@BPartyNo)) ELSE 
                                                                    CASE WHEN ( LEFT(@BPartyNo,2) = '08' AND LEN(@BPartyNo) > 10 ) THEN SUBSTRING(@BPartyNo, 11, LEN(@BPartyNo)) ELSE '' END
                                                                END
                                                            END
                                                        END
                                                    END
                                                END
                                            END
                                        END
                                    END
                        END;
    ELSE
        SELECT @Return = '';

    RETURN @Return
END

Answer 1

它们根本不需要嵌套:

   SELECT @Return = CASE WHEN LEFT(@BPartyNo, 4) = '+610' THEN SUBSTRING('0' + SUBSTRING(@BPartyNo, 5, LEN(@BPartyNo)), 11, LEN( '0' + SUBSTRING(@BPartyNo, 5, LEN(@BPartyNo)) ) )
                         WHEN LEFT(@BPartyNo, 3) = '+61' THEN SUBSTRING('0' + SUBSTRING(@BPartyNo, 4, LEN(@BPartyNo)), 11, LEN( '0' + SUBSTRING(@BPartyNo, 4, LEN(@BPartyNo)) ) )
                         WHEN LEFT(@BPartyNo, 2) = '61' THEN SUBSTRING('0' + SUBSTRING(@BPartyNo, 3, LEN(@BPartyNo)), 11, LEN( '0' + SUBSTRING(@BPartyNo, 3, LEN(@BPartyNo)) ) )
                         WHEN LEFT(@BPartyNo, 6) = '001161' THEN SUBSTRING('0' + SUBSTRING(@BPartyNo, 7, LEN(@BPartyNo)), 11, LEN( '0' + SUBSTRING(@BPartyNo, 7, LEN(@BPartyNo)) ) )
                         WHEN ( LEFT(@BPartyNo,2) = '01' AND LEN(@BPartyNo) > 10 ) THEN SUBSTRING(@BPartyNo, 11, LEN(@BPartyNo))
                         WHEN ( LEFT(@BPartyNo,2) = '02' AND LEN(@BPartyNo) > 10 ) THEN SUBSTRING(@BPartyNo, 11, LEN(@BPartyNo))
                         WHEN ( LEFT(@BPartyNo,2) = '03' AND LEN(@BPartyNo) > 10 ) THEN SUBSTRING(@BPartyNo, 11, LEN(@BPartyNo))
                         WHEN ( LEFT(@BPartyNo,2) = '04' AND LEN(@BPartyNo) > 10 ) THEN SUBSTRING(@BPartyNo, 11, LEN(@BPartyNo))
                         WHEN ( LEFT(@BPartyNo,2) = '07' AND LEN(@BPartyNo) > 10 ) THEN SUBSTRING(@BPartyNo, 11, LEN(@BPartyNo))
                         WHEN ( LEFT(@BPartyNo,2) = '08' AND LEN(@BPartyNo) > 10 ) THEN SUBSTRING(@BPartyNo, 11, LEN(@BPartyNo))
                         ELSE ''
                     END

就个人而言,这样你要确保在消毒后的数据我会调整你的代码输入,而不是试图现在来净化它(当它显然为时已晚......).或者至少用您的客户端语言进行转换(即在调用此sproc的任何内容中),这有望比T-SQL更适合字符串操作的任务.

Answer 2

你不需要嵌套case语句,你可以有很多 WHEN ... THEN

CASE 
    WHEN @x = 1 THEN 1 
    WHEN @x = 2 THEN 2 
    WHEN @x = 3 THEN 3 
    ELSE 4 
END