From 95a6539331aef3d7da0885540478463ff7f36b62 Mon Sep 17 00:00:00 2001
From: Jinzhu <wosmvp@gmail.com>
Date: Sun, 31 May 2020 21:11:20 +0800
Subject: [PATCH] Test Pluck

---
 finisher_api.go     |  1 +
 scan.go             | 32 +++++++++++++++++++++-----------
 tests/query_test.go | 32 ++++++++++++++++++++++++++++++++
 3 files changed, 54 insertions(+), 11 deletions(-)

diff --git a/finisher_api.go b/finisher_api.go
index 49b08fa4..334aea58 100644
--- a/finisher_api.go
+++ b/finisher_api.go
@@ -273,6 +273,7 @@ func (db *DB) Scan(dest interface{}) (tx *DB) {
 //     db.Find(&users).Pluck("age", &ages)
 func (db *DB) Pluck(column string, dest interface{}) (tx *DB) {
 	tx = db.getInstance()
+	tx.Statement.AddClause(clause.Select{Columns: []clause.Column{{Name: column}}})
 	tx.Statement.Dest = dest
 	tx.callbacks.Query().Execute(tx)
 	return
diff --git a/scan.go b/scan.go
index 66cb0b94..4d328fde 100644
--- a/scan.go
+++ b/scan.go
@@ -58,7 +58,12 @@ func Scan(rows *sql.Rows, db *DB, initialized bool) {
 	default:
 		switch db.Statement.ReflectValue.Kind() {
 		case reflect.Slice, reflect.Array:
-			isPtr := db.Statement.ReflectValue.Type().Elem().Kind() == reflect.Ptr
+			reflectValueType := db.Statement.ReflectValue.Type().Elem()
+			isPtr := reflectValueType.Kind() == reflect.Ptr
+			if isPtr {
+				reflectValueType = reflectValueType.Elem()
+			}
+
 			db.Statement.ReflectValue.Set(reflect.MakeSlice(db.Statement.ReflectValue.Type(), 0, 0))
 			fields := make([]*schema.Field, len(columns))
 			joinFields := make([][2]*schema.Field, len(columns))
@@ -81,17 +86,22 @@ func Scan(rows *sql.Rows, db *DB, initialized bool) {
 
 			for initialized || rows.Next() {
 				initialized = false
-				elem := reflect.New(db.Statement.Schema.ModelType).Elem()
-				for idx, field := range fields {
-					if field != nil {
-						values[idx] = field.ReflectValueOf(elem).Addr().Interface()
-					} else if joinFields[idx][0] != nil {
-						relValue := joinFields[idx][0].ReflectValueOf(elem)
-						if relValue.Kind() == reflect.Ptr && relValue.IsNil() {
-							relValue.Set(reflect.New(relValue.Type().Elem()))
-						}
+				elem := reflect.New(reflectValueType).Elem()
 
-						values[idx] = joinFields[idx][1].ReflectValueOf(relValue).Addr().Interface()
+				if reflectValueType.Kind() != reflect.Struct && len(fields) == 1 {
+					values[0] = elem.Addr().Interface()
+				} else {
+					for idx, field := range fields {
+						if field != nil {
+							values[idx] = field.ReflectValueOf(elem).Addr().Interface()
+						} else if joinFields[idx][0] != nil {
+							relValue := joinFields[idx][0].ReflectValueOf(elem)
+							if relValue.Kind() == reflect.Ptr && relValue.IsNil() {
+								relValue.Set(reflect.New(relValue.Type().Elem()))
+							}
+
+							values[idx] = joinFields[idx][1].ReflectValueOf(relValue).Addr().Interface()
+						}
 					}
 				}
 
diff --git a/tests/query_test.go b/tests/query_test.go
index 4388066f..b7c619d7 100644
--- a/tests/query_test.go
+++ b/tests/query_test.go
@@ -80,3 +80,35 @@ func TestFind(t *testing.T) {
 		}
 	}
 }
+
+func TestPluck(t *testing.T) {
+	users := []*User{
+		GetUser("pluck-user1", Config{}),
+		GetUser("pluck-user2", Config{}),
+		GetUser("pluck-user3", Config{}),
+	}
+
+	DB.Create(&users)
+
+	var names []string
+	if err := DB.Model(User{}).Where("name like ?", "pluck-user%").Order("name").Pluck("name", &names).Error; err != nil {
+		t.Errorf("Raise error when pluck name, got %v", err)
+	}
+
+	var ids []int
+	if err := DB.Model(User{}).Where("name like ?", "pluck-user%").Order("name").Pluck("id", &ids).Error; err != nil {
+		t.Errorf("Raise error when pluck id, got %v", err)
+	}
+
+	for idx, name := range names {
+		if name != users[idx].Name {
+			t.Errorf("Unexpected result on pluck name, got %+v", names)
+		}
+	}
+
+	for idx, id := range ids {
+		if int(id) != int(users[idx].ID) {
+			t.Errorf("Unexpected result on pluck id, got %+v", ids)
+		}
+	}
+}