主题：SQL多表查询

Dim cmd As New SQLCommand

Dim dt As DataTable

cmd.CommandTimeOut=60

cmd.C

If(t2.text="")Then

cmd.CommandText = "SELECT count(*) F rom " & "{" & "装配线条码追溯表" & yearstring & monthstring & "} WHERE " & "[JH]='" & jhhString & "'"

 a=cmd.ExecuteScalar

cmd.CommandText = "SELECT count(*) F rom " & "{" & "装配线条码追溯表" & yearstringf & monthstringf & "} WHERE " & "[JH]='" & jhhString & "'"

t3.text=cmd.ExecuteScalar

t3.text=a+t3.text