Add ToDateTimeOffset function

Database/Database.sqlproj

@@ -82,5 +82,7 @@
     <Build Include="Functions\GetZoneAbbreviation.sql" />
     <Build Include="Functions\GetZoneId.sql" />
     <Build Include="Functions\GetZoneId_Inline.sql" />
+    <Build Include="Functions\ToDateTimeOffset.sql" />
+    <Build Include="Functions\ToDateTimeOffset_Inline.sql" />
   </ItemGroup>
 </Project>

Database/Functions/ToDateTimeOffset.sql

@@ -0,0 +1,16 @@
+CREATE FUNCTION [Tzdb].[ToDateTimeOffset]
+(
+    @time DATETIME2,
+    @tz VARCHAR(50)
+)
+RETURNS DATETIMEOFFSET
+BEGIN
+	DECLARE @OffsetMinutes INT;
+
+	SELECT TOP 1 @OffsetMinutes = [OffsetMinutes]
+    FROM [Tzdb].[Intervals] i
+	INNER JOIN Tzdb.GetZoneId_Inline(@tz) z ON i.ZoneId = z.ZoneId
+    WHERE  LocalStart <= @time AND LocalEnd > @time;
+
+	RETURN TODATETIMEOFFSET(@time, @OffsetMinutes);
+END

Database/Functions/ToDateTimeOffset_Inline.sql

@@ -0,0 +1,16 @@
+CREATE FUNCTION [Tzdb].[ToDateTimeOffset_Inline]
+(
+    @time DATETIME2,
+    @tz VARCHAR(50)
+)
+RETURNS TABLE
+WITH SCHEMABINDING
+AS RETURN
+  SELECT TOP 1
+         TODATETIMEOFFSET(@time, ntrvl.[OffsetMinutes])
+         AS [Time]
+  FROM   [Tzdb].[Intervals] ntrvl
+  WHERE  ntrvl.[ZoneId] = (SELECT zn.[ZoneId] FROM [Tzdb].[GetZoneId_Inline](@tz) zn)
+  AND    ntrvl.[LocalStart] <= @time
+  AND    ntrvl.[LocalEnd] > @time;
+GO