Corrected table join conditions for IS NULL expression. Closes #42.

hisystems · Mar 28, 2012 · 959fe37 · 959fe37
1 parent 3027a5a
commit 959fe37
Showing 1 changed file with 11 additions and 4 deletions.
diff --git a/SQL/Select/SQLSelectTableJoinCondition.vb b/SQL/Select/SQLSelectTableJoinCondition.vb
@@ -69,10 +69,17 @@ Namespace SQL
         Friend ReadOnly Property SQL(ByVal eConnectionType As Database.ConnectionType) As String
             Get
 
-                Return _
-                    pobjLeftExpression.SQL(eConnectionType) & " " & _
-                    SQLConvertCompare(Compare) & " " & _
-                    pobjRightExpression.SQL(eConnectionType)
+                'Account for the situation where EqualTo to NULL is appropriately translated to 'IS NULL'
+                If TypeOf pobjRightExpression Is SQLValueExpression Then
+                    Return _
+                        pobjLeftExpression.SQL(eConnectionType) & " " & _
+                        SQLConvertCondition(Compare, DirectCast(pobjRightExpression, SQLValueExpression).Value, eConnectionType)
+                Else
+                    Return _
+                        pobjLeftExpression.SQL(eConnectionType) & " " & _
+                        SQLConvertCompare(Compare) & " " & _
+                        pobjRightExpression.SQL(eConnectionType)
+                End If
 
             End Get
         End Property