diff --git a/chainable_api.go b/chainable_api.go
index afcdccd2..6fa605c6 100644
--- a/chainable_api.go
+++ b/chainable_api.go
@@ -111,21 +111,27 @@ func (db *DB) Omit(columns ...string) (tx *DB) {
 // Where add conditions
 func (db *DB) Where(query interface{}, args ...interface{}) (tx *DB) {
 	tx = db.getInstance()
-	tx.Statement.AddClause(clause.Where{Exprs: tx.Statement.BuildCondtion(query, args...)})
+	if conds := tx.Statement.BuildCondtion(query, args...); len(conds) > 0 {
+		tx.Statement.AddClause(clause.Where{Exprs: conds})
+	}
 	return
 }
 
 // Not add NOT conditions
 func (db *DB) Not(query interface{}, args ...interface{}) (tx *DB) {
 	tx = db.getInstance()
-	tx.Statement.AddClause(clause.Where{Exprs: []clause.Expression{clause.Not(tx.Statement.BuildCondtion(query, args...)...)}})
+	if conds := tx.Statement.BuildCondtion(query, args...); len(conds) > 0 {
+		tx.Statement.AddClause(clause.Where{Exprs: []clause.Expression{clause.Not(conds...)}})
+	}
 	return
 }
 
 // Or add OR conditions
 func (db *DB) Or(query interface{}, args ...interface{}) (tx *DB) {
 	tx = db.getInstance()
-	tx.Statement.AddClause(clause.Where{Exprs: []clause.Expression{clause.Or(tx.Statement.BuildCondtion(query, args...)...)}})
+	if conds := tx.Statement.BuildCondtion(query, args...); len(conds) > 0 {
+		tx.Statement.AddClause(clause.Where{Exprs: []clause.Expression{clause.Or(conds...)}})
+	}
 	return
 }
 
diff --git a/statement.go b/statement.go
index 444d5c37..aa7d193c 100644
--- a/statement.go
+++ b/statement.go
@@ -204,12 +204,15 @@ func (stmt *Statement) AddClauseIfNotExists(v clause.Interface) {
 // BuildCondtion build condition
 func (stmt Statement) BuildCondtion(query interface{}, args ...interface{}) (conds []clause.Expression) {
 	if sql, ok := query.(string); ok {
-		if i, err := strconv.Atoi(sql); err == nil {
-			query = i
-		} else if len(args) == 0 || (len(args) > 0 && strings.Contains(sql, "?")) || strings.Contains(sql, "@") {
-			return []clause.Expression{clause.Expr{SQL: sql, Vars: args}}
-		} else if len(args) == 1 {
-			return []clause.Expression{clause.Eq{Column: sql, Value: args[0]}}
+		// if it is a number, then treats it as primary key
+		if _, err := strconv.Atoi(sql); err != nil {
+			if sql == "" && len(args) == 0 {
+				return
+			} else if len(args) == 0 || (len(args) > 0 && strings.Contains(sql, "?")) || strings.Contains(sql, "@") {
+				return []clause.Expression{clause.Expr{SQL: sql, Vars: args}}
+			} else if len(args) == 1 {
+				return []clause.Expression{clause.Eq{Column: sql, Value: args[0]}}
+			}
 		}
 	}
 
@@ -267,14 +270,12 @@ func (stmt Statement) BuildCondtion(query interface{}, args ...interface{}) (con
 						}
 					}
 				}
+			} else if len(conds) == 0 {
+				conds = append(conds, clause.IN{Column: clause.PrimaryColumn, Values: args})
 			}
 		}
 	}
 
-	if len(conds) == 0 {
-		conds = append(conds, clause.IN{Column: clause.PrimaryColumn, Values: args})
-	}
-
 	return
 }
 
diff --git a/tests/query_test.go b/tests/query_test.go
index a4fe1243..6efadc8e 100644
--- a/tests/query_test.go
+++ b/tests/query_test.go
@@ -1,12 +1,14 @@
 package tests_test
 
 import (
+	"fmt"
 	"reflect"
 	"sort"
 	"strconv"
 	"testing"
 	"time"
 
+	"github.com/jinzhu/gorm"
 	. "github.com/jinzhu/gorm/tests"
 )
 
@@ -115,8 +117,14 @@ func TestPluck(t *testing.T) {
 		t.Errorf("got error when pluck name: %v", err)
 	}
 
+	var names2 []string
+	if err := DB.Model(User{}).Where("name like ?", "pluck-user%").Order("name desc").Pluck("name", &names2).Error; err != nil {
+		t.Errorf("got error when pluck name: %v", err)
+	}
+	AssertEqual(t, names, sort.Reverse(sort.StringSlice(names2)))
+
 	var ids []int
-	if err := DB.Model(User{}).Where("name like ?", "pluck-user%").Order("name").Pluck("id", &ids).Error; err != nil {
+	if err := DB.Model(User{}).Where("name like ?", "pluck-user%").Pluck("id", &ids).Error; err != nil {
 		t.Errorf("got error when pluck id: %v", err)
 	}
 
@@ -133,6 +141,21 @@ func TestPluck(t *testing.T) {
 	}
 }
 
+func TestSelect(t *testing.T) {
+	user := User{Name: "SelectUser1"}
+	DB.Save(&user)
+
+	var result User
+	DB.Where("name = ?", user.Name).Select("name").Find(&result)
+	if result.ID != 0 {
+		t.Errorf("Should not have ID because only selected name, %+v", result.ID)
+	}
+
+	if user.Name != result.Name {
+		t.Errorf("Should have user Name when selected it")
+	}
+}
+
 func TestPluckWithSelect(t *testing.T) {
 	users := []User{
 		{Name: "pluck_with_select_1", Age: 25},
@@ -151,3 +174,175 @@ func TestPluckWithSelect(t *testing.T) {
 
 	AssertEqual(t, userAges, []int{26, 27})
 }
+
+func TestSelectWithVariables(t *testing.T) {
+	DB.Save(&User{Name: "select_with_variables"})
+
+	rows, _ := DB.Table("users").Where("name = ?", "select_with_variables").Select("? as fake", gorm.Expr("name")).Rows()
+
+	if !rows.Next() {
+		t.Errorf("Should have returned at least one row")
+	} else {
+		columns, _ := rows.Columns()
+		AssertEqual(t, columns, []string{"fake"})
+	}
+
+	rows.Close()
+}
+
+func TestSelectWithArrayInput(t *testing.T) {
+	DB.Save(&User{Name: "select_with_array", Age: 42})
+
+	var user User
+	DB.Select([]string{"name", "age"}).Where("age = 42 AND name = ?", "select_with_array").First(&user)
+
+	if user.Name != "select_with_array" || user.Age != 42 {
+		t.Errorf("Should have selected both age and name")
+	}
+}
+
+func TestCustomizedTypePrimaryKey(t *testing.T) {
+	type ID uint
+	type CustomizedTypePrimaryKey struct {
+		ID   ID
+		Name string
+	}
+
+	DB.Migrator().DropTable(&CustomizedTypePrimaryKey{})
+	if err := DB.AutoMigrate(&CustomizedTypePrimaryKey{}); err != nil {
+		t.Fatalf("failed to migrate, got error %v", err)
+	}
+
+	p1 := CustomizedTypePrimaryKey{Name: "p1"}
+	p2 := CustomizedTypePrimaryKey{Name: "p2"}
+	p3 := CustomizedTypePrimaryKey{Name: "p3"}
+	DB.Create(&p1)
+	DB.Create(&p2)
+	DB.Create(&p3)
+
+	var p CustomizedTypePrimaryKey
+
+	if err := DB.First(&p, p2.ID).Error; err != nil {
+		t.Errorf("No error should returns, but got %v", err)
+	}
+
+	AssertEqual(t, p, p2)
+
+	if err := DB.First(&p, "id = ?", p2.ID).Error; err != nil {
+		t.Errorf("No error should happen when querying with customized type for primary key, got err %v", err)
+	}
+
+	AssertEqual(t, p, p2)
+}
+
+func TestStringPrimaryKeyForNumericValueStartingWithZero(t *testing.T) {
+	type AddressByZipCode struct {
+		ZipCode string `gorm:"primary_key"`
+		Address string
+	}
+
+	DB.Migrator().DropTable(&AddressByZipCode{})
+	if err := DB.AutoMigrate(&AddressByZipCode{}); err != nil {
+		t.Fatalf("failed to migrate, got error %v", err)
+	}
+
+	address := AddressByZipCode{ZipCode: "00501", Address: "Holtsville"}
+	DB.Create(&address)
+
+	var result AddressByZipCode
+	DB.First(&result, "00501")
+
+	AssertEqual(t, result, address)
+}
+
+func TestSearchWithEmptyChain(t *testing.T) {
+	user := User{Name: "search_with_empty_chain", Age: 1}
+	DB.Create(&user)
+
+	var result User
+	if DB.Where("").Where("").First(&result).Error != nil {
+		t.Errorf("Should not raise any error if searching with empty strings")
+	}
+
+	if DB.Where(&User{}).Where("name = ?", user.Name).First(&result).Error != nil {
+		t.Errorf("Should not raise any error if searching with empty struct")
+	}
+
+	if DB.Where(map[string]interface{}{}).Where("name = ?", user.Name).First(&result).Error != nil {
+		t.Errorf("Should not raise any error if searching with empty map")
+	}
+}
+
+func TestLimit(t *testing.T) {
+	users := []User{
+		{Name: "LimitUser1", Age: 1},
+		{Name: "LimitUser2", Age: 10},
+		{Name: "LimitUser3", Age: 20},
+		{Name: "LimitUser4", Age: 10},
+		{Name: "LimitUser5", Age: 20},
+	}
+
+	DB.Create(&users)
+
+	var users1, users2, users3 []User
+	DB.Order("age desc").Limit(3).Find(&users1).Limit(5).Find(&users2).Limit(-1).Find(&users3)
+
+	if len(users1) != 3 || len(users2) != 5 || len(users3) <= 5 {
+		t.Errorf("Limit should works")
+	}
+}
+
+func TestOffset(t *testing.T) {
+	for i := 0; i < 20; i++ {
+		DB.Save(&User{Name: fmt.Sprintf("OffsetUser%v", i)})
+	}
+	var users1, users2, users3, users4 []User
+
+	DB.Limit(100).Where("name like ?", "OffsetUser%").Order("age desc").Find(&users1).Offset(3).Find(&users2).Offset(5).Find(&users3).Offset(-1).Find(&users4)
+
+	if (len(users1) != len(users4)) || (len(users1)-len(users2) != 3) || (len(users1)-len(users3) != 5) {
+		t.Errorf("Offset should work")
+	}
+}
+
+func TestSearchWithMap(t *testing.T) {
+	users := []User{
+		*GetUser("map_search_user1", Config{}),
+		*GetUser("map_search_user2", Config{}),
+		*GetUser("map_search_user3", Config{}),
+		*GetUser("map_search_user4", Config{Company: true}),
+	}
+
+	DB.Create(&users)
+
+	var user User
+	DB.First(&user, map[string]interface{}{"name": users[0].Name})
+	CheckUser(t, user, users[0])
+
+	DB.Where(map[string]interface{}{"name": users[1].Name}).First(&user)
+	CheckUser(t, user, users[1])
+
+	var results []User
+	DB.Where(map[string]interface{}{"name": users[2].Name}).Find(&results)
+	if len(results) != 1 {
+		t.Fatalf("Search all records with inline map")
+	}
+
+	CheckUser(t, results[0], users[2])
+
+	var results2 []User
+	DB.Find(&results2, map[string]interface{}{"name": users[3].Name, "company_id": nil})
+	if len(results2) != 0 {
+		t.Errorf("Search all records with inline map containing null value finding 0 records")
+	}
+
+	DB.Find(&results2, map[string]interface{}{"name": users[0].Name, "company_id": nil})
+	if len(results2) != 1 {
+		t.Errorf("Search all records with inline map containing null value finding 1 record")
+	}
+
+	DB.Find(&results2, map[string]interface{}{"name": users[3].Name, "company_id": users[3].CompanyID})
+	if len(results2) != 1 {
+		t.Errorf("Search all records with inline multiple value map")
+	}
+}
diff --git a/tests/scanner_valuer_test.go b/tests/scanner_valuer_test.go
index 04c91ab2..9f91b5d8 100644
--- a/tests/scanner_valuer_test.go
+++ b/tests/scanner_valuer_test.go
@@ -50,6 +50,47 @@ func TestScannerValuer(t *testing.T) {
 	AssertObjEqual(t, data, result, "Name", "Gender", "Age", "Male", "Height", "Birthday", "Password", "Num", "Strings", "Structs")
 }
 
+func TestScannerValuerWithFirstOrCreate(t *testing.T) {
+	DB.Migrator().DropTable(&ScannerValuerStruct{})
+	if err := DB.Migrator().AutoMigrate(&ScannerValuerStruct{}); err != nil {
+		t.Errorf("no error should happen when migrate scanner, valuer struct")
+	}
+
+	data := ScannerValuerStruct{
+		Name:   sql.NullString{String: "name", Valid: true},
+		Gender: &sql.NullString{String: "M", Valid: true},
+		Age:    sql.NullInt64{Int64: 18, Valid: true},
+	}
+
+	var result ScannerValuerStruct
+	tx := DB.Where(data).FirstOrCreate(&result)
+
+	if tx.RowsAffected != 1 {
+		t.Errorf("RowsAffected should be 1 after create some record")
+	}
+
+	if tx.Error != nil {
+		t.Errorf("Should not raise any error, but got %v", tx.Error)
+	}
+
+	AssertObjEqual(t, result, data, "Name", "Gender", "Age")
+
+	if err := DB.Where(data).Assign(ScannerValuerStruct{Age: sql.NullInt64{Int64: 18, Valid: true}}).FirstOrCreate(&result).Error; err != nil {
+		t.Errorf("Should not raise any error, but got %v", err)
+	}
+
+	if result.Age.Int64 != 18 {
+		t.Errorf("should update age to 18")
+	}
+
+	var result2 ScannerValuerStruct
+	if err := DB.First(&result2, result.ID).Error; err != nil {
+		t.Errorf("got error %v when query with %v", err, result.ID)
+	}
+
+	AssertObjEqual(t, result2, result, "ID", "CreatedAt", "UpdatedAt", "Name", "Gender", "Age")
+}
+
 func TestInvalidValuer(t *testing.T) {
 	DB.Migrator().DropTable(&ScannerValuerStruct{})
 	if err := DB.Migrator().AutoMigrate(&ScannerValuerStruct{}); err != nil {
diff --git a/tests/sql_builder_test.go b/tests/sql_builder_test.go
index 4cd40c7a..0aed82a2 100644
--- a/tests/sql_builder_test.go
+++ b/tests/sql_builder_test.go
@@ -80,3 +80,45 @@ func TestRaw(t *testing.T) {
 		t.Error("Raw sql to update records")
 	}
 }
+
+func TestRowsWithGroup(t *testing.T) {
+	users := []User{
+		{Name: "having_user_1", Age: 1},
+		{Name: "having_user_2", Age: 10},
+		{Name: "having_user_1", Age: 20},
+		{Name: "having_user_1", Age: 30},
+	}
+
+	DB.Create(&users)
+
+	rows, err := DB.Select("name, count(*) as total").Table("users").Group("name").Having("name IN ?", []string{users[0].Name, users[1].Name}).Rows()
+	if err != nil {
+		t.Fatalf("got error %v", err)
+	}
+
+	defer rows.Close()
+	for rows.Next() {
+		var name string
+		var total int64
+		rows.Scan(&name, &total)
+
+		if name == users[0].Name && total != 3 {
+			t.Errorf("Should have one user having name %v", users[0].Name)
+		} else if name == users[1].Name && total != 1 {
+			t.Errorf("Should have two users having name %v", users[1].Name)
+		}
+	}
+}
+
+func TestQueryRaw(t *testing.T) {
+	users := []*User{
+		GetUser("row_query_user", Config{}),
+		GetUser("row_query_user", Config{}),
+		GetUser("row_query_user", Config{}),
+	}
+	DB.Create(&users)
+
+	var user User
+	DB.Raw("select * from users WHERE id = ?", users[1].ID).First(&user)
+	CheckUser(t, user, *users[1])
+}