Sql server SQL XQuery—XML数据类型方法的参数1；修改"；必须是字符串文字

我有以下SQL代码片段：

declare @idx int = 1

while (@idx <= @NumThresholds)
begin
    declare @strIdx nvarchar(100) = convert(varchar(100), @idx)
    declare @xqueryString nvarchar(max) = concat('replace value of (//*:ElecTariffElements/*:ThresholdMatrix/*:Thresholds/*:BlockThreshold/text())[', @strIdx, '] with "0"')
    set @xml.modify(@xqueryString)
    set @idx = @idx + 1
end

但是这个然后我得到这个错误：

XQuery[modify（）]：仅限'http://www.w3.org/2001/XMLSchema#decimal?', 'http://www.w3.org/2001/XMLSchema#boolean?'或'node（）*'表达式允许作为谓词，找到'xs:string'

我只想迭代元素并替换值，但这似乎比我预期的要困难得多

非常感谢您的帮助

declare@xml=N'
declare @xml xml = N'
<ElecTariffElements>
<ThresholdMatrix>
<Thresholds>
<BlockThreshold>1</BlockThreshold>
<BlockThreshold>2</BlockThreshold>
<BlockThreshold>3</BlockThreshold>
<BlockThreshold>4</BlockThreshold>
<BlockThreshold>4</BlockThreshold>
</Thresholds>
</ThresholdMatrix>
</ElecTariffElements>
';


declare @idx int = 1;
declare @NumThresholds int = @xml.value('count(//*:ElecTariffElements/*:ThresholdMatrix/*:Thresholds/*:BlockThreshold)', 'int');
select @NumThresholds, @xml;

while (@idx <= @NumThresholds)
begin
    set @xml.modify('replace value of (//*:ElecTariffElements/*:ThresholdMatrix/*:Thresholds/*:BlockThreshold/text())[sql:variable("@idx")][1] with 0');
    select @xml;
    set @idx = @idx + 1;
end

select @xml;

1.
2.
3.
4.
4.
';
声明@idx int=1；
声明@NumThresholds int=@xml.value（'count（/*：electrariffelements/*：ThresholdMatrix/*：Thresholds/*：BlockThreshold）'int'）；
选择@NumThresholds，@xml；
而（@idx
declare @xml xml = N'
<ElecTariffElements>
<ThresholdMatrix>
<Thresholds>
<BlockThreshold>1</BlockThreshold>
<BlockThreshold>2</BlockThreshold>
<BlockThreshold>3</BlockThreshold>
<BlockThreshold>4</BlockThreshold>
<BlockThreshold>4</BlockThreshold>
</Thresholds>
</ThresholdMatrix>
</ElecTariffElements>
';


declare @idx int = 1;
declare @NumThresholds int = @xml.value('count(//*:ElecTariffElements/*:ThresholdMatrix/*:Thresholds/*:BlockThreshold)', 'int');
select @NumThresholds, @xml;

while (@idx <= @NumThresholds)
begin
    set @xml.modify('replace value of (//*:ElecTariffElements/*:ThresholdMatrix/*:Thresholds/*:BlockThreshold/text())[sql:variable("@idx")][1] with 0');
    select @xml;
    set @idx = @idx + 1;
end

select @xml;