从多行字符串 T-SQL 中提取单行值

Question

我有一个包含以下格式的字符串的多行 nvarchar：

@String =  
'ReportHeaderColor{R:98, B:183, G:178} 
ReportHeaderFontColor{R:255, B:255, G:255} 
ReportBodyHeaderColor{R:98, B:183, G:178} 
ReportBodyFontColor{R:255, B:255, G:255}'

我希望能够使用 nvarchar 值 @Attribute = 'ReportHeaderFontColor' 并仅从 @String 中提取包含 @Attribute 值的行

Answer 1

只是另一种方法

示例

Declare @String varchar(max)=  
'ReportHeaderColor{R:98, B:183, G:178}
ReportHeaderFontColor{R:255, B:255, G:255}
ReportBodyHeaderColor{R:98, B:183, G:178}
ReportBodyFontColor{R:255, B:255, G:255}'

Declare @Find varchar(150) = 'ReportHeaderFontColor'

Select value
 From  string_split(replace(replace(@String,'}','}|'),char(13)+char(10),''),'|')
 where charindex(@Find,value)>0

结果

value
ReportHeaderFontColor{R:255, B:255, G:255}

Answer 2

下面如何使用apply 查找要查找的开始/结束位置并使用substring 提取：

declare @Attribute nvarchar(100)= 'ReportHeaderFontColor',

@String nvarchar(max) =
'ReportHeaderColor{R:98, B:183, G:178}
ReportHeaderFontColor{R:255, B:255, G:255}
ReportBodyHeaderColor{R:98, B:183, G:178}
ReportBodyFontColor{R:255, B:255, G:255}';

with s as (select @string as string)
select Substring(string,b.pos,e.pos-b.pos+1)
from s
cross apply(values(charindex(Concat('ReportBodyHeaderColor','{'), string)))b(pos)
cross apply(values(CharIndex('}', string, b.pos)))e(pos)
where b.pos>0;

结果：

ReportHeaderFontColor{R:255, B:255, G:255}

Answer 3

可以通过换行符char(10)分割字符串，然后去掉回车符char(13)，如下：

Declare @Attribute nVarChar(50)= 'ReportHeaderFontColor'
Declare @String nVarChar(max) =  
'ReportHeaderColor{R:98, B:183, G:178} 
ReportHeaderFontColor{R:255, B:255, G:255} 
ReportBodyHeaderColor{R:98, B:183, G:178} 
ReportBodyFontColor{R:255, B:255, G:255}'

Select Replace(Value,Char(13),'') As Result
From String_Split(@String,Char(10))
Where Value Like Concat('%',@Attribute,'%')

Result
ReportHeaderFontColor{R:255, B:255, G:255}

Answer 4

感谢您的所有建议，很遗憾我无法使用 string_split，因为我们的一些客户使用的系统早于 SQL 2016。

玩了一会儿后，我想出了以下解决方案，我将其放在 UDF 中并添加了一些错误检查：

declare @header_row nvarchar(max) = 
'ReportHeaderColor{R:98, B:183, G:178} 
ReportHeaderFontColor{R:255, B:255, G:255} 
ReportBodyHeaderColor{R:98, B:183, G:178} 
ReportBodyFontColor{R:255, B:255, G:255}'

declare @Attribute nvarchar(max) = 'ReportHeaderFontColor'

declare @String nvarchar(255)

-- check that the header row is not empty and actually contains the attribute
if (len(@header_row) = 0 or @header_row not like '%' + @Attribute + '%')
begin
    select @String = null
end
else begin

    select @String = 
        replace(replace(replace(
            left(
                substring(@header_row,charindex(@Attribute + '{', @header_row) + len(@Attribute + '{'), 999),charindex('}',
                substring(@header_row,charindex(@Attribute + '{', @header_row) + len(@Attribute + '{'), 999))-1)
        ,'R:',''),'G:',''),'B:','')

    -- if the string is not in the correct format(3 integers separated by a comma) set @String to null
    if (select count(1)
        from dbo.fn_ListToTable(@String,',') x
        where ISNUMERIC(x.List) = 1 and x.List <= 255) <> 3
    begin
        set @String = null
    end

end