Add support for expression in OFFSET clause.

README.md

@@ -579,5 +579,5 @@ To run the tests, additional dependencies are required:
 
 ## License
 
-Copyright 2019-2023 Goran Bjelanovic  
+Copyright 2019-2024 Goran Bjelanovic  
 Licensed under the Apache License, Version 2.0.

internal/jet/clause.go

@@ -222,16 +222,18 @@ func (l *ClauseLimit) Serialize(statementType StatementType, out *SQLBuilder, op
 
 // ClauseOffset struct
 type ClauseOffset struct {
-	Count int64
+	Count IntegerExpression
 }
 
 // Serialize serializes clause into SQLBuilder
 func (o *ClauseOffset) Serialize(statementType StatementType, out *SQLBuilder, options ...SerializeOption) {
-	if o.Count >= 0 {
+	if is.Nil(o.Count) {
+		return
+	}
+
 	out.NewLine()
 	out.WriteString("OFFSET")
-		out.insertParametrizedArgument(o.Count)
+	o.Count.serialize(statementType, out, options...)
-	}
 }
 
 // ClauseFetch struct

mysql/select_statement.go

@@ -86,7 +86,6 @@ func newSelectStatement(table ReadableTable, projections []Projection) SelectSta
 		newSelect.From.Tables = []jet.Serializer{table}
 	}
 	newSelect.Limit.Count = -1
-	newSelect.Offset.Count = -1
 	newSelect.ShareLock.Name = "LOCK IN SHARE MODE"
 	newSelect.ShareLock.InNewLine = true
 
@@ -158,7 +157,7 @@ func (s *selectStatementImpl) LIMIT(limit int64) SelectStatement {
 }
 
 func (s *selectStatementImpl) OFFSET(offset int64) SelectStatement {
-	s.Offset.Count = offset
+	s.Offset.Count = Int(offset)
 	return s
 }
 

mysql/set_statement.go

@@ -63,7 +63,6 @@ func newSetStatementImpl(operator string, all bool, selects []jet.SerializerStat
 	newSetStatement.setOperator.All = all
 	newSetStatement.setOperator.Selects = selects
 	newSetStatement.setOperator.Limit.Count = -1
-	newSetStatement.setOperator.Offset.Count = -1
 
 	newSetStatement.setOperatorsImpl.parent = newSetStatement
 
@@ -81,7 +80,7 @@ func (s *setStatementImpl) LIMIT(limit int64) setStatement {
 }
 
 func (s *setStatementImpl) OFFSET(offset int64) setStatement {
-	s.setOperator.Offset.Count = offset
+	s.setOperator.Offset.Count = Int(offset)
 	return s
 }
 

postgres/select_statement.go

@@ -53,6 +53,8 @@ type SelectStatement interface {
 	ORDER_BY(orderByClauses ...OrderByClause) SelectStatement
 	LIMIT(limit int64) SelectStatement
 	OFFSET(offset int64) SelectStatement
+	// OFFSET_e can be used when an integer expression is needed as offset, otherwise OFFSET can be used
+	OFFSET_e(offset IntegerExpression) SelectStatement
 	FETCH_FIRST(count IntegerExpression) fetchExpand
 	FOR(lock RowLock) SelectStatement
 
@@ -91,7 +93,6 @@ func newSelectStatement(table ReadableTable, projections []Projection) SelectSta
 		newSelect.From.Tables = []jet.Serializer{table}
 	}
 	newSelect.Limit.Count = -1
-	newSelect.Offset.Count = -1
 
 	newSelect.setOperatorsImpl.parent = newSelect
 
@@ -157,6 +158,11 @@ func (s *selectStatementImpl) LIMIT(limit int64) SelectStatement {
 }
 
 func (s *selectStatementImpl) OFFSET(offset int64) SelectStatement {
+	s.Offset.Count = Int(offset)
+	return s
+}
+
+func (s *selectStatementImpl) OFFSET_e(offset IntegerExpression) SelectStatement {
 	s.Offset.Count = offset
 	return s
 }

postgres/set_statement.go

@@ -45,6 +45,8 @@ type setStatement interface {
 
 	LIMIT(limit int64) setStatement
 	OFFSET(offset int64) setStatement
+	// OFFSET_e can be used when an integer expression is needed as offset, otherwise OFFSET can be used
+	OFFSET_e(offset IntegerExpression) setStatement
 
 	AsTable(alias string) SelectTable
 }
@@ -107,7 +109,6 @@ func newSetStatementImpl(operator string, all bool, selects []jet.SerializerStat
 	newSetStatement.setOperator.All = all
 	newSetStatement.setOperator.Selects = selects
 	newSetStatement.setOperator.Limit.Count = -1
-	newSetStatement.setOperator.Offset.Count = -1
 
 	newSetStatement.setOperatorsImpl.parent = newSetStatement
 
@@ -125,6 +126,11 @@ func (s *setStatementImpl) LIMIT(limit int64) setStatement {
 }
 
 func (s *setStatementImpl) OFFSET(offset int64) setStatement {
+	s.setOperator.Offset.Count = Int(offset)
+	return s
+}
+
+func (s *setStatementImpl) OFFSET_e(offset IntegerExpression) setStatement {
 	s.setOperator.Offset.Count = offset
 	return s
 }

sqlite/select_statement.go

@@ -74,7 +74,6 @@ func newSelectStatement(table ReadableTable, projections []Projection) SelectSta
 		newSelect.From.Tables = []jet.Serializer{table}
 	}
 	newSelect.Limit.Count = -1
-	newSelect.Offset.Count = -1
 	newSelect.ShareLock.Name = "LOCK IN SHARE MODE"
 	newSelect.ShareLock.InNewLine = true
 
@@ -141,7 +140,7 @@ func (s *selectStatementImpl) LIMIT(limit int64) SelectStatement {
 }
 
 func (s *selectStatementImpl) OFFSET(offset int64) SelectStatement {
-	s.Offset.Count = offset
+	s.Offset.Count = Int(offset)
 	return s
 }
 

sqlite/set_statement.go

@@ -63,7 +63,6 @@ func newSetStatementImpl(operator string, all bool, selects []jet.SerializerStat
 	newSetStatement.setOperator.All = all
 	newSetStatement.setOperator.Selects = selects
 	newSetStatement.setOperator.Limit.Count = -1
-	newSetStatement.setOperator.Offset.Count = -1
 	newSetStatement.setOperator.SkipSelectWrap = true
 
 	newSetStatement.setOperatorsImpl.parent = newSetStatement
@@ -82,7 +81,7 @@ func (s *setStatementImpl) LIMIT(limit int64) setStatement {
 }
 
 func (s *setStatementImpl) OFFSET(offset int64) setStatement {
-	s.setOperator.Offset.Count = offset
+	s.setOperator.Offset.Count = Int(offset)
 	return s
 }
 

tests/postgres/select_test.go

@@ -320,6 +320,38 @@ FETCH FIRST (
 	})
 }
 
+func TestOffsetExpression(t *testing.T) {
+
+	stmt := SELECT(Actor.AllColumns).
+		FROM(Actor).
+		ORDER_BY(Actor.ActorID).
+		OFFSET_e(IntExp(
+			SELECT(MAX(Store.StoreID)).
+				FROM(Store),
+		)).LIMIT(10)
+
+	testutils.AssertDebugStatementSql(t, stmt, `
+SELECT actor.actor_id AS "actor.actor_id",
+     actor.first_name AS "actor.first_name",
+     actor.last_name AS "actor.last_name",
+     actor.last_update AS "actor.last_update"
+FROM dvds.actor
+ORDER BY actor.actor_id
+LIMIT 10
+OFFSET (
+     SELECT MAX(store.store_id)
+     FROM dvds.store
+);
+`)
+
+	var dest []model.Actor
+
+	err := stmt.Query(db, &dest)
+	require.NoError(t, err)
+	require.Len(t, dest, 10)
+	require.Equal(t, dest[0].ActorID, int32(3))
+}
+
 func TestJoinQueryStruct(t *testing.T) {
 
 	expectedSQL := `
@@ -2365,16 +2397,14 @@ OFFSET 20;
 		Payment.
 			SELECT(Payment.PaymentID, Payment.Amount).
 			WHERE(Payment.Amount.GT_EQ(Float(200))),
-	).
+	).ORDER_BY(
-		ORDER_BY(IntegerColumn("payment.payment_id").ASC(), Payment.Amount.DESC()).
+		IntegerColumn("payment.payment_id").ASC(),
-		LIMIT(10).
+		Payment.Amount.DESC(),
-		OFFSET(20)
+	).LIMIT(10).OFFSET(20)
-
-	//fmt.Println(query.DebugSql())
 
 	testutils.AssertDebugStatementSql(t, query, expectedQuery, float64(100), float64(200), int64(10), int64(20))
 
-	dest := []model.Payment{}
+	var dest []model.Payment
 
 	err := query.Query(db, &dest)
 
@@ -2394,6 +2424,56 @@ OFFSET 20;
 	})
 }
 
+func TestUnionOffsetWithExpression(t *testing.T) {
+	stmt := UNION(
+		SELECT(Rental.AllColumns).
+			FROM(Rental).
+			WHERE(Rental.ReturnDate.IS_NULL()),
+
+		SELECT(Rental.AllColumns).
+			FROM(Rental).
+			WHERE(Rental.LastUpdate.GT(LOCALTIMESTAMP())),
+	).OFFSET_e(IntExp(
+		SELECT(Int32(3)),
+	)).LIMIT(10)
+
+	testutils.AssertStatementSql(t, stmt, `
+(
+     SELECT rental.rental_id AS "rental.rental_id",
+          rental.rental_date AS "rental.rental_date",
+          rental.inventory_id AS "rental.inventory_id",
+          rental.customer_id AS "rental.customer_id",
+          rental.return_date AS "rental.return_date",
+          rental.staff_id AS "rental.staff_id",
+          rental.last_update AS "rental.last_update"
+     FROM dvds.rental
+     WHERE rental.return_date IS NULL
+)
+UNION
+(
+     SELECT rental.rental_id AS "rental.rental_id",
+          rental.rental_date AS "rental.rental_date",
+          rental.inventory_id AS "rental.inventory_id",
+          rental.customer_id AS "rental.customer_id",
+          rental.return_date AS "rental.return_date",
+          rental.staff_id AS "rental.staff_id",
+          rental.last_update AS "rental.last_update"
+     FROM dvds.rental
+     WHERE rental.last_update > LOCALTIMESTAMP
+)
+LIMIT $1
+OFFSET (
+     SELECT $2::integer
+);
+`)
+
+	var dest []model.Rental
+
+	err := stmt.Query(db, &dest)
+	require.NoError(t, err)
+	require.Len(t, dest, 10)
+}
+
 func TestAllSetOperators(t *testing.T) {
 	var select1 = Payment.SELECT(Payment.AllColumns).WHERE(Payment.PaymentID.GT_EQ(Int(17600)).AND(Payment.PaymentID.LT(Int(17610))))
 	var select2 = Payment.SELECT(Payment.AllColumns).WHERE(Payment.PaymentID.GT_EQ(Int(17620)).AND(Payment.PaymentID.LT(Int(17630))))