SQL Server Update Query says table already exits - sql

Question

I have two tables in my database - MPRS and ALL_SSC. I want to update the ALL_SSC table with data from MPRS and in Access (where I test my SQL) it works.
However, when I run it in my VB 2010 program on the SQL Server database, it says table MPRS already exists.
I know it does! I'm not trying to create it. I'm updating FROM it... any ideas where this SQL is wrong?
SQL = "UPDATE ALL_SSC LEFT JOIN MPRS ON MPRS.MPAN = ALL_SSC.MPAN1 SET ALL_SSC.PC1 = Format([mprs].[pc],'00'), ALL_SSC.MSPCDC1 = Mid([mprs].[PC_EFD],7,4) & Mid([mprs].[PC_EFD],4,2) & Mid([mprs].[PC_EFD],1,2), ALL_SSC.MTSC1 = [mprs].[MTC], ALL_SSC.MSMCDC1 = Mid([mprs].[MTC_EFD],7,4) & Mid([mprs].[MTC_EFD],4,2) & Mid([mprs].[MTC_EFD],1,2), ALL_SSC.LLF1 = [mprs].[LLF], ALL_SSC.SUPPLIER1 = [mprs].[SUPPLIER], ALL_SSC.REGI1 = Mid([mprs].[SSD],7,4) & Mid([mprs].[SSD],4,2) & Mid([mprs].[SSD],1,2), ALL_SSC.ENG_STATUS1 = 0 WHERE (((ALL_SSC.MPAN1) Is Not Null) AND ([mprs].[ENERG_STATUS]='E'));"
cmd = New SqlCommand(sSQL, cNN)
Try
Try
If cNN.State <> ConnectionState.Open Then
cNN.Open()
End If
Catch exCnn As Exception
MsgBox(exCnn.Message)
End Try
cmd.ExecuteNonQuery()
Catch ex As Exception
MsgBox("Cannot continue. " & ex.Message)
Exit Sub
End Try

Answer 1

You have accidentally used variable "sSQL" when you meant to use "SQL".
Yet another example of why meaningful variable names are important.

Answer 2

The correct syntax for a JOIN with UPDATE in SQL Server is:
UPDATE a
SET PC1 = . . .
FROM ALL_SSC a LEFT JOIN
MPRS m
ON m.MPAN = a.MPAN1
WHERE . . .;
That is, you need a FROM clause and it comes after the SET.

Answer 3

Thanks Gordon for your help. One or two other changes needed to move from Access SQL to SQL Server, but this is the SQL i ended up with working in SQL Server.
UPDATE a
SET
a.PC1 = '0' + m.[pc],
a.MSPCDC1 = substring(m.[PC_EFD],7,4) + substring(m.[PC_EFD],4,2) + substring(m.[PC_EFD],1,2),
a.MTSC1 = m.[MTC],
a.MSMCDC1 = substring(m.[MTC_EFD],7,4) +substring(m.[MTC_EFD],4,2) + substring(m.[MTC_EFD],1,2),
a.LLF1 = m.[LLF],
a.SUPPLIER1 = m.[SUPPLIER],
a.REGI1 = substring(m.[SSD],7,4) + substring(m.[SSD],4,2) + substring(m.[SSD],1,2),
a.ENG_STATUS1 = 0
FROM [myDataBase].[dbo].ALL_SSC a LEFT JOIN
[myDataBase].[dbo].MPRS m
ON m.MPAN = a.MPAN1
WHERE (((a.MPAN1) Is Not Null) AND (m.[ENERG_STATUS]='E'));
However, When I execute the exact same code on the database via VB 2010, I get the same failure message. This is the vb code
For iMPAN As Integer = 1 To 3
'mpan - energised
SQL = "UPDATE a SET a.PC" + iMPAN.ToString + " = '0' + m.[pc], a.MSPCDC" + iMPAN.ToString + " = substring(m.[PC_EFD],7,4) + substring(m.[PC_EFD],4,2) + substring(m.[PC_EFD],1,2), a.MTSC" + iMPAN.ToString + " = m.[MTC], a.MSMCDC" + iMPAN.ToString + " = substring(m.[MTC_EFD],7,4) +substring(m.[MTC_EFD],4,2) + substring(m.[MTC_EFD],1,2), a.LLF" + iMPAN.ToString + " = m.[LLF], a.SUPPLIER" + iMPAN.ToString + " = m.[SUPPLIER], a.REGI" + iMPAN.ToString + " = substring(m.[SSD],7,4) + substring(m.[SSD],4,2) + substring(m.[SSD],1,2), a.ENG_STATUS" + iMPAN.ToString + " = 0 FROM ALL_SSC a LEFT JOIN MPRS m ON m.MPAN = a.MPAN1 WHERE (((a.MPAN" + iMPAN.ToString + ") Is Not Null) AND (m.[ENERG_STATUS]='E'));"
Debug.Print(SQL)
cmd = New SqlCommand(sSQL, cNN)
Try
Try
If cNN.State <> ConnectionState.Open Then
cNN.Open()
End If
Catch exCnn As Exception
MsgBox(exCnn.Message)
End Try
cmd.ExecuteNonQuery()
Catch ex As Exception
Debug.Print(ex.Message)
MsgBox("Cannot continue. " & ex.Message)
Exit Sub
End Try
Next