From 3dee88794941e10c83674c954cc4baea5d2c3942 Mon Sep 17 00:00:00 2001
From: "thinh.le" <thinh.le@hellohealthgroup.com>
Date: Tue, 17 Dec 2024 14:19:20 +0700
Subject: [PATCH] feat: add support for engine

---
 ch/query_test.go                   | 30 +++++++++++++++++++++++++++++-
 ch/query_view_create.go            | 28 ++++++++++++++++++++++++----
 ch/testdata/snapshots/TestQuery-20 |  1 +
 ch/testdata/snapshots/TestQuery-21 |  1 +
 4 files changed, 55 insertions(+), 5 deletions(-)
 create mode 100644 ch/testdata/snapshots/TestQuery-20
 create mode 100644 ch/testdata/snapshots/TestQuery-21

diff --git a/ch/query_test.go b/ch/query_test.go
index 136d3ab..26c7812 100644
--- a/ch/query_test.go
+++ b/ch/query_test.go
@@ -134,6 +134,35 @@ func TestQuery(t *testing.T) {
 				OnCluster("my-cluster").
 				IfNotExists()
 		},
+		func(db *ch.DB) chschema.QueryAppender {
+			return db.NewCreateView().
+				Materialized().
+				Engine("MergeTree").
+				IfNotExists().
+				View("view_name").
+				Column("col1").
+				ColumnExpr("col1 AS alias").
+				TableExpr("src_table AS alias").
+				Where("foo = bar").
+				Group("group1").
+				GroupExpr("group2, group3").
+				OrderExpr("order2, order3")
+		},
+		func(db *ch.DB) chschema.QueryAppender {
+			return db.NewCreateView().
+				Materialized().
+				Engine("MergeTree").
+				To("dest_table"). // expect override engine
+				IfNotExists().
+				View("view_name").
+				Column("col1").
+				ColumnExpr("col1 AS alias").
+				TableExpr("src_table AS alias").
+				Where("foo = bar").
+				Group("group1").
+				GroupExpr("group2, group3").
+				OrderExpr("order2, order3")
+		},
 	}
 
 	db := chDB()
@@ -145,7 +174,6 @@ func TestQuery(t *testing.T) {
 	for i, fn := range queries {
 		t.Run(fmt.Sprintf("%d", i), func(t *testing.T) {
 			q := fn(db)
-
 			query, err := q.AppendQuery(db.Formatter(), nil)
 			if err != nil {
 				snapshot.SnapshotT(t, err.Error())
diff --git a/ch/query_view_create.go b/ch/query_view_create.go
index 8a672bc..5a04f6e 100644
--- a/ch/query_view_create.go
+++ b/ch/query_view_create.go
@@ -14,6 +14,7 @@ type CreateViewQuery struct {
 	materialized bool
 	ifNotExists  bool
 	view         chschema.QueryWithArgs
+	engine       chschema.QueryWithArgs
 	onCluster    chschema.QueryWithArgs
 	to           chschema.QueryWithArgs
 	where        whereQuery
@@ -62,6 +63,7 @@ func (q *CreateViewQuery) OnClusterExpr(query string, args ...any) *CreateViewQu
 	return q
 }
 
+// will disable engine option
 func (q *CreateViewQuery) To(to string) *CreateViewQuery {
 	q.to = chschema.UnsafeName(to)
 	return q
@@ -84,6 +86,11 @@ func (q *CreateViewQuery) TableExpr(query string, args ...any) *CreateViewQuery
 	return q
 }
 
+func (q *CreateViewQuery) Engine(query string, args ...any) *CreateViewQuery {
+	q.engine = chschema.SafeQuery(query, args)
+	return q
+}
+
 func (q *CreateViewQuery) ModelTableExpr(query string, args ...any) *CreateViewQuery {
 	q.modelTableName = chschema.SafeQuery(query, args)
 	return q
@@ -205,11 +212,24 @@ func (q *CreateViewQuery) AppendQuery(fmter chschema.Formatter, b []byte) (_ []b
 		}
 	}
 
-	b = append(b, " TO "...)
-	b, err = q.to.AppendQuery(fmter, b)
-	if err != nil {
-		return nil, err
+	if !q.to.IsEmpty() {
+		b = append(b, " TO "...)
+		b, err = q.to.AppendQuery(fmter, b)
+		if err != nil {
+			return nil, err
+		}
 	}
+
+	// clickhouse do not support both to and engine
+	if !q.engine.IsEmpty() && q.to.IsEmpty() {
+		b = append(b, " Engine = "...)
+
+		b, err = q.engine.AppendQuery(fmter, b)
+		if err != nil {
+			return nil, err
+		}
+	}
+
 	b = append(b, " AS "...)
 
 	b = append(b, "SELECT "...)
diff --git a/ch/testdata/snapshots/TestQuery-20 b/ch/testdata/snapshots/TestQuery-20
new file mode 100644
index 0000000..11e8db8
--- /dev/null
+++ b/ch/testdata/snapshots/TestQuery-20
@@ -0,0 +1 @@
+CREATE MATERIALIZED VIEW IF NOT EXISTS "view_name" Engine = MergeTree AS SELECT "col1", col1 AS alias FROM src_table AS alias WHERE (foo = bar) GROUP BY "group1", group2, group3 ORDER BY order2, order3
diff --git a/ch/testdata/snapshots/TestQuery-21 b/ch/testdata/snapshots/TestQuery-21
new file mode 100644
index 0000000..2d8c1d8
--- /dev/null
+++ b/ch/testdata/snapshots/TestQuery-21
@@ -0,0 +1 @@
+CREATE MATERIALIZED VIEW IF NOT EXISTS "view_name" TO "dest_table" AS SELECT "col1", col1 AS alias FROM src_table AS alias WHERE (foo = bar) GROUP BY "group1", group2, group3 ORDER BY order2, order3