declare @tssj nvarchar(100)  -- 外部變量
declare @Sql_Sql nvarchar(100) -- 存sql字符串變量

      set @Sql_Sql =N'select @tssj=jpk from b where bzmc=''中國'''

EXEC sp_executesql @Sql_Sql,N'@tssj int output',@tssj output
select @tssj