From 093694fbf2922a3dff56059504ead6974399febf Mon Sep 17 00:00:00 2001
From: Sec Cake <nozhangsicong@qq.com>
Date: Fri, 20 Aug 2021 18:06:48 +0800
Subject: [PATCH] Fix extra 'AND' when len(values) == 0 ON IN.NegationBuild()
 (#4618)

---
 clause/expression.go | 4 ++--
 tests/query_test.go  | 5 +++++
 2 files changed, 7 insertions(+), 2 deletions(-)

diff --git a/clause/expression.go b/clause/expression.go
index a177c5d8..f7b93f4c 100644
--- a/clause/expression.go
+++ b/clause/expression.go
@@ -210,11 +210,12 @@ func (in IN) Build(builder Builder) {
 }
 
 func (in IN) NegationBuild(builder Builder) {
+	builder.WriteQuoted(in.Column)
 	switch len(in.Values) {
 	case 0:
+		builder.WriteString(" IS NOT NULL")
 	case 1:
 		if _, ok := in.Values[0].([]interface{}); !ok {
-			builder.WriteQuoted(in.Column)
 			builder.WriteString(" <> ")
 			builder.AddVar(builder, in.Values[0])
 			break
@@ -222,7 +223,6 @@ func (in IN) NegationBuild(builder Builder) {
 
 		fallthrough
 	default:
-		builder.WriteQuoted(in.Column)
 		builder.WriteString(" NOT IN (")
 		builder.AddVar(builder, in.Values...)
 		builder.WriteByte(')')
diff --git a/tests/query_test.go b/tests/query_test.go
index 36046aee..8a476598 100644
--- a/tests/query_test.go
+++ b/tests/query_test.go
@@ -436,6 +436,11 @@ func TestNot(t *testing.T) {
 		t.Fatalf("Build NOT condition, but got %v", result.Statement.SQL.String())
 	}
 
+	result = dryDB.Not(map[string]interface{}{"name": []string{}}).Find(&User{})
+	if !regexp.MustCompile("SELECT \\* FROM .*users.* WHERE .*name.* IS NOT NULL").MatchString(result.Statement.SQL.String()) {
+		t.Fatalf("Build NOT condition, but got %v", result.Statement.SQL.String())
+	}
+	
 	result = dryDB.Not(map[string]interface{}{"name": []string{"jinzhu", "jinzhu 2"}}).Find(&User{})
 	if !regexp.MustCompile("SELECT \\* FROM .*users.* WHERE .*name.* NOT IN \\(.+,.+\\)").MatchString(result.Statement.SQL.String()) {
 		t.Fatalf("Build NOT condition, but got %v", result.Statement.SQL.String())