TSQL:判断某较短字符串在较长字符串中出现的次数。

给定一个较短字符串shortStr='ab'，和一个较长字符串longStr='adkdabkwelabwkereabrsdweo2342ablk234lksdfsdf1abe'；

判断shortStr在longStr中出现的次数的方案，要求使用sql实现：

方案一：使用replace函数：

declare @llongStr nvarchar(64)
declare @shortStr nvarchar(16);
set @llongStr='adkdabkwelabwkereabrsdweo2342ablk234lksdfsdf1abe';
set @shortStr='ab';

declare @newStr nvarchar(64);
set @newStr=replace(@llongStr,@shortStr,'');

declare @shortDisplayCount int;
set @shortDisplayCount=(len(@llongStr)-len(@newStr))/len(@shortStr);

select @shortDisplayCount;

打印结果：

方案二：使用charindex和substring实现：

declare @longStr nvarchar(64)
declare @shortStr nvarchar(16);
set @longStr='adkdabkwelabwkereabrsdweo2342ablk234lksdfsdf1abe';
set @shortStr='ab';       

declare @findCount int;     
declare @idx int;
set @findCount=0;

while charindex(@shortstr,@longStr)>0
begin
    set @findCount+=1;
    set @idx=charindex(@shortstr,@longStr)
    
    set @longStr=substring(@longStr,@idx+len(@shortStr),len(@longStr)-@idx);
    print @longStr         
end

print @findCount

输出结果：

kwelabwkereabrsdweo2342ablk234lksdfsdf1abe
wkereabrsdweo2342ablk234lksdfsdf1abe
rsdweo2342ablk234lksdfsdf1abe
lk234lksdfsdf1abe
e
5