feat: Advanced Update and Delete support (CTEs, Order, Limit)

pkg/dialect/dialect_test.go

@@ -134,7 +134,7 @@ func TestPostgresDialect(t *testing.T) {
 	if got := d.Name(); got != "postgres" {
 		t.Fatalf("unexpected name: %q", got)
 	}
-	if got := d.Features(); got != FeatureInsertReturning|FeatureUpdateReturning|FeatureDeleteReturning|FeatureOffset|FeatureUpsert|FeatureCTE|FeatureDefaultPlaceholder|FeatureSavepoint|FeatureSelectLocking|FeatureNullsOrder|FeatureSelectDistinctOn {
+	if got := d.Features(); got != FeatureInsertReturning|FeatureUpdateReturning|FeatureDeleteReturning|FeatureOffset|FeatureUpsert|FeatureCTE|FeatureDefaultPlaceholder|FeatureSavepoint|FeatureSelectLocking|FeatureNullsOrder|FeatureSelectDistinctOn|FeatureUnlimited {
 		t.Fatalf("unexpected features: %b", got)
 	}
 	if got := d.QuoteIdentifier(`user"name`); got != `"user""name"` {
@@ -193,10 +193,10 @@ func TestPostgresDialect(t *testing.T) {
 	if got := d.LimitOffset(10, 0); got != "LIMIT 10" {
 		t.Fatalf("unexpected limit only clause: %q", got)
 	}
-	if got := d.LimitOffset(0, 20); got != "OFFSET 20" {
+	if got := d.LimitOffset(0, 20); got != "LIMIT 0 OFFSET 20" {
 		t.Fatalf("unexpected offset only clause: %q", got)
 	}
-	if got := d.LimitOffset(0, 0); got != "" {
+	if got := d.LimitOffset(0, 0); got != "LIMIT 0" {
 		t.Fatalf("unexpected empty limit clause: %q", got)
 	}
 	if got := d.UpsertClause("users", []string{"email"}, []string{"name"}); got != "ON CONFLICT DO UPDATE" {
@@ -224,7 +224,7 @@ func TestMySQLDialect(t *testing.T) {
 	if got := d.Name(); got != "mysql" {
 		t.Fatalf("unexpected name: %q", got)
 	}
-	if got := d.Features(); got != FeatureOffset|FeatureUpsert|FeatureSavepoint|FeatureSelectLocking {
+	if got := d.Features(); got != FeatureOffset|FeatureUpsert|FeatureSavepoint|FeatureSelectLocking|FeatureCTE|FeatureUpdateOrder|FeatureUpdateLimit|FeatureDeleteOrder|FeatureDeleteLimit|FeatureUnlimited {
 		t.Fatalf("unexpected features: %b", got)
 	}
 	if got := d.QuoteIdentifier("user`name"); got != "`user``name`" {
@@ -283,10 +283,10 @@ func TestMySQLDialect(t *testing.T) {
 	if got := d.LimitOffset(10, 0); got != "LIMIT 10" {
 		t.Fatalf("unexpected limit only clause: %q", got)
 	}
-	if got := d.LimitOffset(0, 20); got != "LIMIT 18446744073709551615 OFFSET 20" {
+	if got := d.LimitOffset(0, 20); got != "LIMIT 20, 0" {
 		t.Fatalf("unexpected offset only clause: %q", got)
 	}
-	if got := d.LimitOffset(0, 0); got != "" {
+	if got := d.LimitOffset(0, 0); got != "LIMIT 0" {
 		t.Fatalf("unexpected empty limit clause: %q", got)
 	}
 	if got := d.UpsertClause("users", []string{"email"}, []string{"name"}); got != "ON DUPLICATE KEY UPDATE" {
@@ -314,7 +314,7 @@ func TestSQLiteDialect(t *testing.T) {
 	if got := d.Name(); got != "sqlite" {
 		t.Fatalf("unexpected name: %q", got)
 	}
-	if got := d.Features(); got != FeatureInsertReturning|FeatureUpdateReturning|FeatureDeleteReturning|FeatureOffset|FeatureUpsert|FeatureSavepoint|FeatureNullsOrder {
+	if got := d.Features(); got != FeatureInsertReturning|FeatureUpdateReturning|FeatureDeleteReturning|FeatureOffset|FeatureUpsert|FeatureSavepoint|FeatureNullsOrder|FeatureCTE|FeatureUpdateOrder|FeatureUpdateLimit|FeatureDeleteOrder|FeatureDeleteLimit|FeatureUnlimited {
 		t.Fatalf("unexpected features: %b", got)
 	}
 	if got := d.QuoteIdentifier(`user"name`); got != `"user""name"` {
@@ -368,10 +368,10 @@ func TestSQLiteDialect(t *testing.T) {
 	if got := d.LimitOffset(10, 0); got != "LIMIT 10" {
 		t.Fatalf("unexpected limit only clause: %q", got)
 	}
-	if got := d.LimitOffset(0, 20); got != "LIMIT -1 OFFSET 20" {
+	if got := d.LimitOffset(0, 20); got != "LIMIT 0 OFFSET 20" {
 		t.Fatalf("unexpected offset only clause: %q", got)
 	}
-	if got := d.LimitOffset(0, 0); got != "" {
+	if got := d.LimitOffset(0, 0); got != "LIMIT 0" {
 		t.Fatalf("unexpected empty limit clause: %q", got)
 	}
 	if got := d.UpsertClause("users", []string{"email"}, []string{"name"}); got != "ON CONFLICT DO UPDATE" {

pkg/dialect/feature.go

@@ -15,6 +15,11 @@ const (
 	FeatureSelectLocking
 	FeatureNullsOrder
 	FeatureSelectDistinctOn
+	FeatureUpdateOrder
+	FeatureUpdateLimit
+	FeatureDeleteOrder
+	FeatureDeleteLimit
+	FeatureUnlimited
 )
 
 // HasFeature reports whether a feature set includes the requested capability.

pkg/dialect/mysql.go

@@ -19,7 +19,16 @@ func (d *MySQLDialect) Name() string {
 
 // Features returns MySQL capabilities supported by Rain.
 func (d *MySQLDialect) Features() Feature {
-	return FeatureOffset | FeatureUpsert | FeatureSavepoint | FeatureSelectLocking
+	return FeatureOffset |
+		FeatureUpsert |
+		FeatureSavepoint |
+		FeatureSelectLocking |
+		FeatureCTE |
+		FeatureUpdateOrder |
+		FeatureUpdateLimit |
+		FeatureDeleteOrder |
+		FeatureDeleteLimit |
+		FeatureUnlimited
 }
 
 // QuoteIdentifier quotes identifiers with backticks.
@@ -93,7 +102,7 @@ func (d *MySQLDialect) AutoIncrementKeyword() string {
 
 // LimitOffset returns MySQL LIMIT/OFFSET syntax.
 func (d *MySQLDialect) LimitOffset(limit, offset int) string {
-	if limit > 0 {
+	if limit >= 0 {
 		if offset > 0 {
 			return "LIMIT " + strconv.Itoa(offset) + ", " + strconv.Itoa(limit)
 		}

pkg/dialect/postgres.go

@@ -30,7 +30,8 @@ func (d *PostgresDialect) Features() Feature {
 		FeatureSavepoint |
 		FeatureSelectLocking |
 		FeatureNullsOrder |
-		FeatureSelectDistinctOn
+		FeatureSelectDistinctOn |
+		FeatureUnlimited
 }
 
 // QuoteIdentifier quotes identifiers with double quotes.
@@ -104,10 +105,10 @@ func (d *PostgresDialect) AutoIncrementKeyword() string {
 
 // LimitOffset returns PostgreSQL LIMIT/OFFSET syntax.
 func (d *PostgresDialect) LimitOffset(limit, offset int) string {
-	if limit > 0 && offset > 0 {
-		return "LIMIT " + strconv.Itoa(limit) + " OFFSET " + strconv.Itoa(offset)
-	}
-	if limit > 0 {
+	if limit >= 0 {
+		if offset > 0 {
+			return "LIMIT " + strconv.Itoa(limit) + " OFFSET " + strconv.Itoa(offset)
+		}
 		return "LIMIT " + strconv.Itoa(limit)
 	}
 	if offset > 0 {

pkg/dialect/sqlite.go

@@ -25,7 +25,13 @@ func (d *SQLiteDialect) Features() Feature {
 		FeatureOffset |
 		FeatureUpsert |
 		FeatureSavepoint |
-		FeatureNullsOrder
+		FeatureNullsOrder |
+		FeatureCTE |
+		FeatureUpdateOrder |
+		FeatureUpdateLimit |
+		FeatureDeleteOrder |
+		FeatureDeleteLimit |
+		FeatureUnlimited
 }
 
 // QuoteIdentifier quotes identifiers with double quotes.
@@ -76,7 +82,7 @@ func (d *SQLiteDialect) AutoIncrementKeyword() string {
 
 // LimitOffset returns SQLite LIMIT/OFFSET syntax.
 func (d *SQLiteDialect) LimitOffset(limit, offset int) string {
-	if limit > 0 {
+	if limit >= 0 {
 		if offset > 0 {
 			return "LIMIT " + strconv.Itoa(limit) + " OFFSET " + strconv.Itoa(offset)
 		}

pkg/rain/query_common.go

@@ -88,3 +88,86 @@ func closeRows(rows *sql.Rows, errp *error) {
 		*errp = err
 	}
 }
+
+func writeCTEs(ctx *compileContext, ctes []cteDefinition, label string) error {
+	if len(ctes) == 0 || ctx.skipCTEs {
+		return nil
+	}
+	if !dialect.HasFeature(ctx.dialect.Features(), dialect.FeatureCTE) {
+		return fmt.Errorf("rain: %s queries do not support CTEs for %s dialect", label, ctx.dialect.Name())
+	}
+	ctx.writeString("WITH ")
+	for idx, cte := range ctes {
+		if idx > 0 {
+			ctx.writeString(", ")
+		}
+		if strings.TrimSpace(cte.name) == "" {
+			return errors.New("rain: CTE name cannot be empty")
+		}
+		if cte.query == nil {
+			return fmt.Errorf("rain: CTE %q requires a query", cte.name)
+		}
+		if len(cte.query.ctes) > 0 {
+			return fmt.Errorf("rain: CTE %q body cannot itself contain CTEs", cte.name)
+		}
+		ctx.writeQuotedIdentifier(cte.name)
+		ctx.writeString(" AS (")
+		if err := cte.query.writeSQL(ctx); err != nil {
+			return err
+		}
+		ctx.writeByte(')')
+	}
+	ctx.writeByte(' ')
+	return nil
+}
+
+func writeOrderLimit(ctx *compileContext, order []schema.OrderExpr, limit *int, offset *int, featureOrder, featureLimit dialect.Feature) error {
+	if len(order) > 0 {
+		if featureOrder != dialect.FeatureUnlimited && !dialect.HasFeature(ctx.dialect.Features(), featureOrder) {
+			return fmt.Errorf("rain: ORDER BY is not supported for this query type in %s dialect", ctx.dialect.Name())
+		}
+		ctx.writeString(" ORDER BY ")
+		for idx, item := range order {
+			if idx > 0 {
+				ctx.writeString(", ")
+			}
+			if err := ctx.writeExpression(item.Expr); err != nil {
+				return err
+			}
+			ctx.writeByte(' ')
+			ctx.writeString(string(item.Direction))
+			if item.NullsOrder != "" {
+				if !dialect.HasFeature(ctx.dialect.Features(), dialect.FeatureNullsOrder) {
+					return fmt.Errorf("rain: NULLS FIRST/LAST is not supported by %s dialect", ctx.dialect.Name())
+				}
+				ctx.writeByte(' ')
+				ctx.writeString(string(item.NullsOrder))
+			}
+		}
+	}
+
+	if limit != nil || (offset != nil && *offset > 0) {
+		if featureLimit != dialect.FeatureUnlimited && !dialect.HasFeature(ctx.dialect.Features(), featureLimit) {
+			return fmt.Errorf("rain: LIMIT/OFFSET is not supported for this query type in %s dialect", ctx.dialect.Name())
+		}
+		l := -1
+		if limit != nil {
+			l = *limit
+			if l < 0 {
+				return errors.New("rain: LIMIT must be non-negative")
+			}
+		}
+		o := 0
+		if offset != nil {
+			o = *offset
+			if o < 0 {
+				return errors.New("rain: OFFSET must be non-negative")
+			}
+		}
+		if clause := ctx.dialect.LimitOffset(l, o); clause != "" {
+			ctx.writeByte(' ')
+			ctx.writeString(clause)
+		}
+	}
+	return nil
+}

pkg/rain/query_delete.go

@@ -16,6 +16,9 @@ type DeleteQuery struct {
 	dialect   dialect.Dialect
 	table     *schema.TableDef
 	where     []schema.Predicate
+	order     []schema.OrderExpr
+	limit     *int
+	ctes      []cteDefinition
 	returning []schema.Expression
 	unbounded bool
 }
@@ -38,6 +41,26 @@ func (q *DeleteQuery) Returning(exprs ...schema.Expression) *DeleteQuery {
 	return q
 }
 
+// With appends a common table expression definition.
+func (q *DeleteQuery) With(name string, query *SelectQuery) *DeleteQuery {
+	q.ctes = append(q.ctes, cteDefinition{name: name, query: query})
+	return q
+}
+
+// OrderBy appends ORDER BY expressions.
+// Supported by MySQL and SQLite.
+func (q *DeleteQuery) OrderBy(order ...schema.OrderExpr) *DeleteQuery {
+	q.order = append(q.order, order...)
+	return q
+}
+
+// Limit sets the LIMIT clause.
+// Supported by MySQL and SQLite.
+func (q *DeleteQuery) Limit(limit int) *DeleteQuery {
+	q.limit = &limit
+	return q
+}
+
 // Unbounded allows DELETE without a WHERE clause.
 func (q *DeleteQuery) Unbounded() *DeleteQuery {
 	q.unbounded = true
@@ -58,6 +81,11 @@ func (q *DeleteQuery) ToSQL() (string, []any, error) {
 
 	ctx := newCompileContext(q.dialect)
 	defer releaseCompileContext(ctx)
+
+	if err := writeCTEs(ctx, q.ctes, "delete"); err != nil {
+		return "", nil, err
+	}
+
 	ctx.writeString("DELETE FROM ")
 	ctx.writeTableName(q.table)
 	if len(q.where) > 0 {
@@ -67,6 +95,10 @@ func (q *DeleteQuery) ToSQL() (string, []any, error) {
 		}
 	}
 
+	if err := writeOrderLimit(ctx, q.order, q.limit, nil, dialect.FeatureDeleteOrder, dialect.FeatureDeleteLimit); err != nil {
+		return "", nil, err
+	}
+
 	if err := ctx.writeReturning(q.returning, q.returningClause()); err != nil {
 		return "", nil, err
 	}