Update using two tables in Ms access vba - sql

Question

I want to update a table using numbers from another table, I want to do the following formla
Y-X(1)-(A1+A2+A3)
X is form table1 while Y,A1,A2,A3 from table2. The new record wil be updated in column X where the ID has only one of the records = 0
Table1
ID || X
-------------
1 || **0**
1 || 155
2 || 4
3 || 0
3 || 0
3 || 234
4 || 0
4 || 0
Table2
ID || Y || A1 || A2 || A3
--------------------------------------
1 || 228 || 1 || 3 || 4
2 || 112 || 6 || 7 || 7
3 || 4 || 22 || 1 || 0
4 || 78 || 76 || 6 || 2
from the above example tables the only column that will match the certiria is ID=1 where only one of them is 0 and the count = 2 so column X
where =0 will be updated ( X2= 228-155-(1+3+4))
Updated table1
ID || X
-------------
1 || **65**
1 || 155
2 || 4
3 || 0
3 || 0
3 || 234
4 || 0
4 || 0
My code is
Private Sub GET_TWO_INJLINE_EST()
DoCmd.SetWarnings False
DoCmd.RunSQL "UPDATE table1 I, table2 P" _
& " SET I.X = IIf(I.X = 0, DLookup(""P.Y-I.X-(P.A1 + P.A2 + P.A3)"" , " _
& " ""table1"", ""[ID]="" & [ID] & "" AND I.X <> 0""), I.X)" _
& " WHERE I.[ID] IN (SELECT I.[ID] FROM table1 I" _
& " GROUP BY I.[ID] HAVING (Count(I.[ID]) = 2)" _
& " AND (Min(I.ID) <> Max(I.X))" _
& " AND (Min(I.X) = 0 OR Max(I.X) = 0))" _
& " AND I.ID=P.ID"
DoCmd.SetWarnings True
End Sub
when I run it show me "Unknown" error.

Answer 1

Consider an UPDATE ... INNER JOIN query and reconciling your DLookUp as you attempt to pass I.X within the string expression. Furthermore, your subquery's Min() <> Max() equality does not compare to same X.
Finally, consider saving the update query as a stored Access query without concatenating in a VBA string which avoids the double quoting and forces you to check syntax error prior to saving. Plus, the database engine caches and pre-compiles for best execution plan.
SQL (save as Access stored query; see DMax inside larger expression)
UPDATE table1 I
INNER JOIN table2 P ON I.ID = P.ID
SET I.X = IIF(I.X=0, (P.Y - DMax("X", "table1", "ID=" & I.ID) - (P.A1+P.A2+P.A3)), I.X)
WHERE I.[ID] IN
(SELECT sub.[ID]
FROM table1 sub
GROUP BY sub.[ID]
HAVING (Count(sub.[ID]) = 2)
AND (Min(sub.X) <> Max(sub.X))
AND (Min(sub.X) = 0 OR Max(sub.X) = 0))
VBA
Private Sub GET_TWO_INJLINE_EST()
DoCmd.SetWarnings True
DoCmd.OpenQuery "mySavedUpdateQuery"
DoCmd.SetWarnings True
End Sub

Answer 2

try changing the second table1 I to table1 J and update all the references to the second table1
UPDATE table1 I, table2 P
Set I.X = IIf(I.X = 0,
DLookup(""P.Y-I.X-(P.A1 + P.A2 + P.A3)"",
""table1"",
""[ID]="" & [ID] & "" AND I.X <> 0""
),
I.X
)
WHERE I.[ID] IN (
SELECT J.[ID] FROM table1 J
GROUP BY J.[ID]
HAVING (Count(J.[ID]) = 2)
AND (Min(J.ID) <> Max(J.X))
AND (Min(J.X) = 0 OR Max(J.X) = 0))
AND J.ID=P.ID