From 418c60c83cf8472d883bb9ab8b9821444e7c8f0a Mon Sep 17 00:00:00 2001
From: kinggo <30891428+longlihale@users.noreply.github.com>
Date: Sat, 9 Oct 2021 16:55:45 +0800
Subject: [PATCH] fixed: clauseSelect.Columns missed when use Join And execute
 multiple query. (#4757)

---
 callbacks/query.go  | 13 ++++++-------
 tests/joins_test.go | 27 +++++++++++++++++++++++++++
 2 files changed, 33 insertions(+), 7 deletions(-)

diff --git a/callbacks/query.go b/callbacks/query.go
index 1cfd618c..0eee2a43 100644
--- a/callbacks/query.go
+++ b/callbacks/query.go
@@ -95,7 +95,12 @@ func BuildQuerySQL(db *gorm.DB) {
 		}
 
 		// inline joins
-		if len(db.Statement.Joins) != 0 {
+		joins := []clause.Join{}
+		if fromClause, ok := db.Statement.Clauses["FROM"].Expression.(clause.From); ok {
+			joins = fromClause.Joins
+		}
+
+		if len(db.Statement.Joins) != 0 || len(joins) != 0 {
 			if len(db.Statement.Selects) == 0 && db.Statement.Schema != nil {
 				clauseSelect.Columns = make([]clause.Column, len(db.Statement.Schema.DBNames))
 				for idx, dbName := range db.Statement.Schema.DBNames {
@@ -103,12 +108,6 @@ func BuildQuerySQL(db *gorm.DB) {
 				}
 			}
 
-			joins := []clause.Join{}
-
-			if fromClause, ok := db.Statement.Clauses["FROM"].Expression.(clause.From); ok {
-				joins = fromClause.Joins
-			}
-
 			for _, join := range db.Statement.Joins {
 				if db.Statement.Schema == nil {
 					joins = append(joins, clause.Join{
diff --git a/tests/joins_test.go b/tests/joins_test.go
index 25fa20b4..ca8477dc 100644
--- a/tests/joins_test.go
+++ b/tests/joins_test.go
@@ -157,3 +157,30 @@ func TestJoinsWithSelect(t *testing.T) {
 		t.Errorf("Should find all two pets with Join select, got %+v", results)
 	}
 }
+
+func TestJoinCount(t *testing.T) {
+	companyA := Company{Name: "A"}
+	companyB := Company{Name: "B"}
+	DB.Create(&companyA)
+	DB.Create(&companyB)
+
+	user := User{Name: "kingGo", CompanyID: &companyB.ID}
+	DB.Create(&user)
+
+	query := DB.Model(&User{}).Joins("Company")
+	//Bug happens when .Count is called on a query.
+	//Removing the below two lines or downgrading to gorm v1.20.12 will make this test pass.
+	var total int64
+	query.Count(&total)
+
+	var result User
+
+	// Incorrectly generates a 'SELECT *' query which causes companies.id to overwrite users.id
+	if err := query.First(&result, user.ID).Error; err != nil {
+		t.Fatalf("Failed, got error: %v", err)
+	}
+
+	if result.ID != user.ID {
+		t.Fatalf("result's id, %d, doesn't match user's id, %d", result.ID, user.ID)
+	}
+}