Implement returning method on SQL Server

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() {

delete_test.go

@@ -129,7 +129,7 @@ func TestDeleteBuilderReturning(t *testing.T) {
 	a.Equal("DELETE FROM user WHERE id = ? RETURNING id, deleted_at", sql)
 
 	sql, _ = db.BuildWithFlavor(SQLServer)
-	a.Equal("DELETE FROM user WHERE id = @p1", sql)
+	a.Equal("DELETE FROM user OUTPUT DELETED.id, DELETED.deleted_at WHERE id = @p1", sql)
 
 	sql, _ = db.BuildWithFlavor(CQL)
 	a.Equal("DELETE FROM user WHERE id = ?", sql)

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)

insert_test.go

@@ -275,7 +275,7 @@ func TestInsertBuilderReturning(test *testing.T) {
 	a.Equal("INSERT INTO user (name) VALUES (?) RETURNING id", sql)
 
 	sql, _ = ib.BuildWithFlavor(SQLServer)
-	a.Equal("INSERT INTO user (name) VALUES (@p1)", sql)
+	a.Equal("INSERT INTO user (name) OUTPUT INSERTED.id VALUES (@p1)", sql)
 
 	sql, _ = ib.BuildWithFlavor(CQL)
 	a.Equal("INSERT INTO user (name) VALUES (?)", sql)

stringbuilder.go

@@ -56,6 +56,16 @@ func (sb *stringBuilder) WriteStrings(ss []string, sep string) {
 	}
 }
 
+func (sb *stringBuilder) WriteStringsPrefixed(prefix string, ss []string, sep string) {
+	prefixedSs := []string{}
+
+	for _, s := range ss {
+		prefixedSs = append(prefixedSs, prefix+s)
+	}
+
+	sb.WriteStrings(prefixedSs, sep)
+}
+
 func (sb *stringBuilder) WriteRune(r rune) {
 	sb.builder.WriteRune(r)
 }

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 {

update_test.go

@@ -197,7 +197,7 @@ func TestUpdateBuilderReturning(t *testing.T) {
 	a.Equal("UPDATE user SET name = ? WHERE id = ? RETURNING id, updated_at", sql)
 
 	sql, _ = ub.BuildWithFlavor(SQLServer)
-	a.Equal("UPDATE user SET name = @p1 WHERE id = @p2", sql)
+	a.Equal("UPDATE user SET name = @p1 OUTPUT INSERTED.id, INSERTED.updated_at WHERE id = @p2", sql)
 
 	sql, _ = ub.BuildWithFlavor(CQL)
 	a.Equal("UPDATE user SET name = ? WHERE id = ?", sql)