请教一句多列比较的SQL

sunsoncheng

现在有A\B\C\D四个列都存放着对边部的加工工艺,

A\B对应着高,C\D对就着宽

我用如下的语句得到了初步的结果,:

                        "  case" & _
                        "   when A1.高边 =  A1.高2 and A1.高边  = '' then  ''              " & _
                        "   when A1.高边 =  A1.高2 and A1.高边 <> '' then  '高'+A1.高边    " & _
                        "   when A1.高边 <> A1.高2 and A1.高2   = '' then  '单高1'+A1.高边 " & _
                        "   when A1.高边 <> A1.高2 and A1.高边  = '' then  '单高2'+A1.高2  " & _
                        "   else '高1'+A1.高边 +  '高2'+A1.高2  " & _
                        "  End + " & _
                        "  case" & _
                        "   when A1.宽边 =  A1.宽2 and A1.宽边  = '' then  ''              " & _
                        "   when A1.宽边 =  A1.宽2 and A1.宽边 <> '' then  '宽'+A1.宽边    " & _
                        "   when A1.宽边 <> A1.宽2 and A1.宽2   = '' then  '单宽1'+A1.宽边 " & _
                        "   when A1.宽边 <> A1.宽2 and A1.宽边  = '' then  '单宽2'+A1.宽2  " & _
                        "   else '宽1'+A1.宽边 +  '宽2'+A1.宽2  " & _
                        "  End + " & _
现在想要当ABCD全部相同 且又不为空时,时,就简单地用  周A 来表示即可

以前用ACC时用 iif 且里面可套用  iif 就好象没什么事,现在要一个个列出来可真有点湖涂了 那位指点下?谢了

[em06]

sunsoncheng

粗略估算一下不少于25种可能,全部要列出来?

sunsoncheng

想了个怪招,供大家参考,呵呵

                        "  case" & _
                        "   when A1.高边 =  A1.高2 and A1.高边 =  A1.宽边 and A1.高边 = A1.宽2  and  A1.高边  <> '' then  '周'+A1.高边   " & _
                        "   when A1.高边 =  A1.高2 and A1.高边  = '' then  ''              " & _
                        "   when A1.高边 =  A1.高2 and A1.高边 <> '' then  '高'+A1.高边    " & _
                        "   when A1.高边 <> A1.高2 and A1.高2   = '' then  '单高1'+A1.高边 " & _
                        "   when A1.高边 <> A1.高2 and A1.高边  = '' then  '单高2'+A1.高2  " & _
                        "   else '高1'+A1.高边 +  '高2'+A1.高2  " & _
                        "  End + " & _
                        "  case" & _
                        "   when A1.高边 =  A1.高2 and A1.高边 =  A1.宽边 and A1.高边 = A1.宽2  and  A1.高边  <> '' then  ''   " & _
                        "   when A1.宽边 =  A1.宽2 and A1.宽边  = '' then  ''              " & _
                        "   when A1.宽边 =  A1.宽2 and A1.宽边 <> '' then  '宽'+A1.宽边    " & _
                        "   when A1.宽边 <> A1.宽2 and A1.宽2   = '' then  '单宽1'+A1.宽边 " & _
                        "   when A1.宽边 <> A1.宽2 and A1.宽边  = '' then  '单宽2'+A1.宽2  " & _
                        "   else '宽1'+A1.宽边 +  '宽2'+A1.宽2  " & _
                        "  End + " & _

[此贴子已经被作者于2007-4-4 9:31:41编辑过]

ldy888

够怪的, 还没见过 这样用 then 的. 学习了