主题：sql 问题

(Case when len(b.gysddhm)>=12 Then
                 (Case when (len(b.gysddhm)=13 Or len(b.gysddhm)=15) Then SubString(b.gysddhm,1,len(b.gysddhm)-1)+'1'   else  

                    (Case when (len(b.gysddhm)=17 and b.cpx='DP') then SubString(b.gysddhm,1,len(b.gysddhm)-                 

                        5)+'1'+SubString(b.gysddhm,len(b.gysddhm)-3,1)+'1'+ SubString(b.gysddhm,len(b.gysddhm)-1,2) else  

                                     SubString(b.gysddhm,1,len(b.gysddhm)-2)+'1'+SubString(b.gysddhm,len(b.gysddhm),1) end)
               end) 

            else '456' end)