SQL自定义函数split 将数组(分隔字符串)返回阵列（表）

Create FUNCTION [dbo].[SplitToTable]
 (
     @SplitString nvarchar(max),
     @Separator nvarchar(10)=' '
 )
 RETURNS @SplitStringsTable TABLE
 (
 [id] int identity(1,1),
 [value] nvarchar(max)
 )
 AS
 BEGIN
     DECLARE @CurrentIndex int;
     DECLARE @NextIndex int;
     DECLARE @ReturnText nvarchar(max);
     SELECT @CurrentIndex=1;
     WHILE(@CurrentIndex<=len(@SplitString))
         BEGIN
             SELECT @NextIndex=charindex(@Separator,@SplitString,@CurrentIndex);
             IF(@NextIndex=0 OR @NextIndex IS NULL)
                 SELECT @NextIndex=len(@SplitString)+1;
                 SELECT @ReturnText=substring(@SplitString,@CurrentIndex,@NextIndex-@CurrentIndex);
                 INSERT INTO @SplitStringsTable([value]) VALUES(@ReturnText);
                 SELECT @CurrentIndex=@NextIndex+1;
             END
     RETURN;
 END

select * FROm dbo.SplitToTable('111,b2222,323232,32d,e,323232f,g3222', ',')

结果为

id          value
----------- ---------------------------------------
1           111
2           b2222
3           323232
4           32d
5           e
6           323232f
7           g3222

(7 行受影响)

使用循环的方法

首先GetSplitLength函数返回分割后的字符数组的长度。

 Create function [dbo].[GetSplitLength]
 (
  @String nvarchar(max),  --要分割的字符串
  @Split nvarchar(10)  --分隔符号
 )
 returns int
 as
 begin
  declare @location int
  declare @start int
  declare @length int
 
  set @String=ltrim(rtrim(@String))
  set @location=charindex(@split,@String)
  set @length=1
  while @location<>0
  begin
    set @start=@location+1
    set @location=charindex(@split,@String,@start)
    set @length=@length+1
  end
  return @length
 end

select dbo.GetSplitLength('111,b2222,323232,32d,e,323232f,g3222',',')

结果为7。

GetSplitOfIndex函数是按顺序分别获取分割后的字符串。

 ALTER function [dbo].[GetSplitOfIndex]
 (
  @String nvarchar(max),  --要分割的字符串
  @split nvarchar(10),  --分隔符号
  @index int --取第几个元素
 )
 returns nvarchar(1024)
 as
 begin
  declare @location int
  declare @start int
  declare @next int
  declare @seed int
 
  set @String=ltrim(rtrim(@String))
  set @start=1
  set @next=1
  set @seed=len(@split)
  
  set @location=charindex(@split,@String)
  while @location<>0 and @index>@next
  begin
    set @start=@location+@seed
    set @location=charindex(@split,@String,@start)
    set @next=@next+1
  end
  if @location =0 select @location =len(@String)+1 
  
  return substring(@String,@start,@location-@start)
 end

select dbo.GetSplitOfIndex('111,b2222,323232,32d,e,323232f,g3222',',', 3)

结果323232。

 DECLARE @Tags nvarchar(max);
 SELECT @Tags='111,b2222,323232,32d,e,323232f,g3222';
 DECLARE @Tag nvarchar(1000)
 DECLARE @next int;
 set @next=1
 
 DECLARE @Length int;
 SELECT @Length=dbo.GetSplitLength(@Tags,',')

 while @next<=@Length
 begin
     SET @Tag = left(dbo.GetSplitOfIndex(@Tags,',',@next), 16);
     print @Tag
     SET @Next=@Next+1;
 END

结果为：

111
b2222
323232
32d
e
323232f
g3222