Add support for running TSQL or non database-agnostic SQL functions. C…

…loses #2.

DatabaseObjects.vbproj

@@ -191,6 +191,7 @@
     <Compile Include="SQL\Expressions\SQLExpression.vb" />
     <Compile Include="SQL\Expressions\SQLFieldAggregateExpression.vb" />
     <Compile Include="SQL\Expressions\SQLFieldExpression.vb" />
+    <Compile Include="SQL\Expressions\SQLFunctionExpression.vb" />
     <Compile Include="SQL\Expressions\SQLGetDateFunctionExpression.vb" />
     <Compile Include="SQL\Expressions\SQLLeftExpression.vb" />
     <Compile Include="SQL\Select\SQLSelectHavingCondition.vb" />

SQL/Expressions/SQLFunctionExpression.vb

@@ -0,0 +1,60 @@
+
+' ___________________________________________________
+'
+'  © Hi-Integrity Systems 2010. All rights reserved.
+'  www.hisystems.com.au - Toby Wicks
+' ___________________________________________________
+'
+
+Option Strict On
+Option Explicit On
+
+Imports System.Linq
+
+Namespace SQL
+
+    ''' <summary>
+    ''' Allows an SQL function to utilised in a WHERE clause or as a calculated column.
+    ''' </summary>
+    ''' <remarks>
+    ''' Typically used to access a non database-agnostic function.
+    ''' </remarks>
+    Public Class SQLFunctionExpression
+        Inherits SQLExpression
+
+        Private pstrFunctionName As String
+        Private pobjFunctionArguments As SQLExpression()
+
+        Public Sub New(strFunctionName As String)
+
+            If String.IsNullOrEmpty(strFunctionName) Then
+                Throw New ArgumentNullException
+            End If
+
+            pstrFunctionName = strFunctionName
+
+        End Sub
+
+        Public Sub New(strFunctionName As String, ParamArray arguments() As SQLExpression)
+
+            Me.New(strFunctionName)
+
+            pobjFunctionArguments = arguments
+
+        End Sub
+
+        Friend Overrides Function SQL(ByVal eConnectionType As Database.ConnectionType) As String
+
+            Dim strArguments As String = String.Empty
+
+            If pobjFunctionArguments IsNot Nothing Then
+                strArguments = String.Join(", ", pobjFunctionArguments.Select(Function(argument) argument.SQL(eConnectionType)).ToArray)
+            End If
+
+            Return pstrFunctionName & "(" & strArguments & ")"
+
+        End Function
+
+    End Class
+
+End Namespace