二表SUM后合并，为何得出错误结果？
单表各自求和的结果是正确的，但二表求和后合并的结果是错误的。如下图
请问：
（1）正确的语句是什么？
（2）XP系统下access2000中不支持ISNULL吗？空值处本想显示为“0”，但报错
（3）最想要的full join，但报错的，是VB6不支持的吗？
谢谢！！！
moretable.zip
(16.38 KB)
程序代码：Dim cn As ADODB.Connection
Dim rs1, rs2, rs3 As ADODB.Recordset
Private Sub Form_Load()
Set cn = New ADODB.Connection
cn.Open "Provider=Microsoft.Jet.OLEDB.4.0;Data Source= " & App.Path & "\rc.mdb"
'//////////////////////////
Set rs1 = New ADODB.Recordset
rs1.Open "select 编号,规格,sum(数量) as 已生产 from sc group by 编号,规格 ", cn, adOpenStatic, adLockOptimistic
If rs1.RecordCount > 0 Then
Set MSHFlexGrid1.DataSource = rs1
Else
Exit Sub
End If
'///////////////////////////
Set rs2 = New ADODB.Recordset
rs2.Open "select 编号,sum(数量) as 已包装 from bz group by 编号 ", cn, adOpenStatic, adLockOptimistic
If rs2.RecordCount > 0 Then
Set MSHFlexGrid2.DataSource = rs2
Else
Exit Sub
End If
'///////////////////////////
Set rs3 = New ADODB.Recordset
rs3.Open "select sc.编号,sc.规格,sum(sc.数量) as 已生产, sum(bz.数量) as 已包装 from sc left join bz on sc.编号=bz.编号 group by sc.编号,sc.规格 ", cn, adOpenStatic, adLockOptimistic
If rs3.RecordCount > 0 Then
Set MSHFlexGrid3.DataSource = rs3
Else
Exit Sub
End If
rs1.Close
rs2.Close
rs3.Close
cn.Close
Set rs1 = Nothing
Set rs2 = Nothing
Set rs3 = Nothing
Set cn = Nothing
End Sub
[此贴子已经被作者于2020-8-10 20:36编辑过]
