拆分字符串函数

本函数可以将“目标字符串”以“指定字符串”进行拆分，并通过表结构返回结果。

在SQL Service中的代码如下：

CREATE FUNCTION [dbo].[fnSPLIT]
(
    @sInputString varchar(8000) 
    , @sSplitChar varchar(10)
)RETURNS @tbl_List TABLE (SEQ INT IDENTITY(1,1),COD varchar(8000) )
AS

BEGIN
    DECLARE @lInputStringLength Int ,
            @lPosition Int ,
            @lSplitChar Int 

    SET @lInputStringLength = LEN ( @sInputString )
    SET @lPosition=1
    SET @lSplitChar=1

    WHILE @lPosition <= @lInputStringLength
        BEGIN
            SET @lSplitChar = CHARINDEX ( @sSplitChar , @sInputString , @lPosition)
            IF @lSplitChar = 0
                BEGIN
                    INSERT @tbl_List (COD )
                    SELECT SUBSTRING( @sInputString , @lPosition ,1+ @lInputStringLength - @lPosition)
                    SET @lPosition= @lInputStringLength + 1
                END
            ELSE
                BEGIN
                    INSERT @tbl_List ( COD )
                    SELECT SUBSTRING( @sInputString , @lPosition , @lSplitChar - @lPosition)
                    SET @lPosition = @lSplitChar+1
        END
    END
    
    DELETE @tbl_List WHERE RTRIM(COD)=''

    RETURN
END

返回结果：

SELECT * FROM dbo.fnSPLIT('我的未来不是梦,我的心跟着希望在动',',')

在Oracle中的代码如下：

--在Type中的代码：
CREATE OR REPLACE TYPE str_split IS TABLE OF VARCHAR2 (4000);

--在Function中的代码：
CREATE OR REPLACE FUNCTION fnSPLIT
(
    P_InputString IN VARCHAR2, 
    P_Flag IN VARCHAR2
)
    RETURN str_split 
    PIPELINED
AS
    v_length   NUMBER := LENGTH(P_InputString);
    v_start    NUMBER := 1;
    v_index    NUMBER;
BEGIN
    WHILE(v_start <= v_length)
    LOOP
        v_index := INSTR(P_InputString, P_Flag, v_start);

        IF v_index = 0
        THEN
            PIPE ROW(SUBSTR(P_InputString, v_start));
            v_start := v_length + 1;
        ELSE
            PIPE ROW(SUBSTR(P_InputString, v_start, v_index - v_start));
            v_start := v_index + 1;
        END IF;
    END LOOP;

    RETURN;
END fnSPLIT;

返回结果：

select * from (select rownum rn,t.* from table(fnSPLIT('我的未来不是梦,我的心跟着希望在动',',')) t)

将行转为列显示：

select a.column_value a,b.column_value b from 
  (select * from (select rownum column_id,t.* from table(fnSPLIT('我的未来不是梦,我的心跟着希望在动',',')) t)) a,
  (select * from (select rownum column_id,t.* from table(fnSPLIT('我的未来不是梦,我的心跟着希望在动',',')) t)) b
where a.column_id=1 and b.column_id=2