asp.net - SQL Get Rows With A Similar Column Value -

i have database stores duplicate rows, duplicate not clear cut, e.g. following 2 column values duplicate:

g12345 & g1234 --> because similar  (a string comparison shows characters match 83.3%). 

i need writing sql query retrieve values similar string sent part of query, e.g. on 50% of characters matched.

can this? have c# method follows not quite sure how accomplish in sql:

static double stringcompare(string a, string b) {   if (a == b) //same string, no iteration needed.     return 100;   if ((a.length == 0) || (b.length == 0)) //one empty, second not   {     return 0;   }   var maxlen = a.length > b.length ? a.length : b.length;   var minlen = a.length < b.length ? a.length : b.length;   var samecharatindex = 0;   (var = 0; < minlen; i++) //compare char char   {     if (a[i] == b[i])     {       samecharatindex++;     }   }   return samecharatindex / maxlen * 100; } 

thanks in advance.

not sure if trying use sql-server or mysql, create , use following function in sql-server:

create function stringcompare     (@a nvarchar(200),     @b nvarchar(200)     ) returns float begin     if (         @a = @b         or (@a null , @b null)         )     begin         return 100.0     end      if (         ((@a null or len(@a) = 0) , (@b not null , len(@b) > 0))         or ((@b null or len(@b) = 0) , (@a not null , len(@a) > 0))         )     begin         return 0.0     end      declare @maxlen int     set @maxlen = case when len(@a) > len(@b) len(@a) else len(@b) end      declare @minlen int     set @minlen = case when len(@a) < len(@b) len(@a) else len(@b) end      declare @samecharatindex int     set @samecharatindex = 0      declare @count int     set @count = 1      while (@count <= @minlen)     begin         if (substring(@a, @count, 1) = substring(@b, @count, 1))         begin             set @samecharatindex = @samecharatindex + 1         end          set @count = @count + 1     end      return cast(@samecharatindex float) / cast(@maxlen float) * 100.0  end 

which used in statement follows:

select dbo.stringcompare('test', 'test'), dbo.stringcompare('nope', 'test'),  dbo.stringcompare('partial', 'parsomethingelse') 

please note, having loop in sql running on many records can inefficient. , may want consider whether have in sql.