Add returning support on SQL Server

Author: Bugadinho

delete.go

@@ -223,6 +223,15 @@ func (db *DeleteBuilder) BuildWithFlavor(flavor Flavor, initialArg ...interface{
 
 	db.injection.WriteTo(buf, deleteMarkerAfterDeleteFrom)
 
+	if flavor == SQLServer {
+		if len(db.returning) > 0 {
+			buf.WriteLeadingString("OUTPUT ")
+			buf.WriteStringsPrefixed("DELETED.", db.returning, ", ")
+		}
+
+		db.injection.WriteTo(buf, insertMarkerAfterReturning)
+	}
+
 	if db.WhereClause != nil {
 		db.whereClauseProxy.WhereClause = db.WhereClause
 		defer func() {

insert.go

@@ -200,6 +200,15 @@ func (ib *InsertBuilder) BuildWithFlavor(flavor Flavor, initialArg ...interface{
 		ib.injection.WriteTo(buf, insertMarkerAfterCols)
 	}
 
+	if flavor == SQLServer {
+		if len(ib.returning) > 0 {
+			buf.WriteLeadingString("OUTPUT ")
+			buf.WriteStringsPrefixed("INSERTED.", ib.returning, ", ")
+		}
+
+		ib.injection.WriteTo(buf, insertMarkerAfterReturning)
+	}
+
 	if ib.sbHolder != "" {
 		buf.WriteString(" ")
 		buf.WriteString(ib.sbHolder)

update.go

@@ -301,6 +301,15 @@ func (ub *UpdateBuilder) BuildWithFlavor(flavor Flavor, initialArg ...interface{
 
 	ub.injection.WriteTo(buf, updateMarkerAfterSet)
 
+	if flavor == SQLServer {
+		if len(ub.returning) > 0 {
+			buf.WriteLeadingString("OUTPUT ")
+			buf.WriteStringsPrefixed("INSERTED.", ub.returning, ", ")
+		}
+
+		ub.injection.WriteTo(buf, insertMarkerAfterReturning)
+	}
+
 	if flavor != MySQL {
 		// For ISO SQL, CTE table names should be written after FROM keyword.
 		if ub.cteBuilder != nil {