#region 计算字符串相似度         /// <summary>         /// 计算字符串相似度         /// </summary>         /// <param name="str1">字符串1</param>         /// <param name="str2">字符串2</param>         /// <returns>相似度</returns>         public static float Levenshtein(string str1, string str2)         {             //计算两个字符串的长度。              int len1 = str1.Length;             int len2 = str2.Length;             //比字符长度大一个空间              int[,] dif = new int[len1 + 1, len2 + 1];             //赋初值，步骤B。              for (int a = 0; a <= len1; a++)             {                 dif[a, 0] = a;             }             for (int a = 0; a <= len2; a++)             {                 dif[0, a] = a;             }             //计算两个字符是否一样，计算左上的值              int temp;             for (int i = 1; i <= len1; i++)             {                 for (int j = 1; j <= len2; j++)                 {                     if (str1.Substring(i - 1, 1) == str2.Substring(j - 1, 1))                     {                         temp = 0;                     }                     else                     {                         temp = 1;                     }                     //取三个值中最小的                      dif[i, j] = Min(dif[i - 1, j - 1] + temp, dif[i, j - 1] + 1, dif[i - 1, j] + 1);                 }             }             return 1 - (float)dif[len1, len2] / Math.Max(str1.Length, str2.Length);         }         #endregion         //比较3个数字得到最小值          private static int Min(int i, int j, int k)         {             return i < j ? (i < k ? i : k) : (j < k ? j : k);         }

CREATE   function get_semblance_By_2words ( @word1 varchar(50), @word2 varchar(50)   ) returns nvarchar(4000) as begin declare @re int declare @maxLenth int declare @i int,@l int declare @tb1 table(child varchar(50)) declare @tb2 table(child varchar(50)) set @i=1 set @l=2 set @maxLenth=len(@word1) if len(@word1)<len(@word2)  begin set @maxLenth=len(@word2) end while @l<=len(@word1)  begin while @i<len(@word1)-1 begin insert @tb1 (child) values( SUBSTRING(@word1,@i,@l) )  set @i=@i+1 end set @i=1 set @l=@l+1 end set @i=1 set @l=2 while @l<=len(@word2)  begin while @i<len(@word2)-1 begin insert @tb2 (child) values( SUBSTRING(@word2,@i,@l) )  set @i=@i+1 end set @i=1 set @l=@l+1 end   select @re=isnull(max( len(a.child)*100/  @maxLenth ) ,0) from @tb1 a, @tb2 b where a.child=b.child return @re end GO   --测试 --select dbo.get_semblance_By_2words('我是谁','我是谁啊')  --75 --相似度