diff --git a/create_test.go b/create_test.go
index 36472914..83b3a4ef 100644
--- a/create_test.go
+++ b/create_test.go
@@ -27,7 +27,9 @@ func TestCreate(t *testing.T) {
 	}
 
 	var newUser User
-	DB.First(&newUser, user.Id)
+	if err := DB.First(&newUser, user.Id).Error; err != nil {
+		t.Errorf("No error should happen, but got %v", err)
+	}
 
 	if !reflect.DeepEqual(newUser.PasswordHash, []byte{'f', 'a', 'k', '4'}) {
 		t.Errorf("User's PasswordHash should be saved ([]byte)")
@@ -38,7 +40,7 @@ func TestCreate(t *testing.T) {
 	}
 
 	if newUser.UserNum != Num(111) {
-		t.Errorf("User's UserNum should be saved (custom type)")
+		t.Errorf("User's UserNum should be saved (custom type), but got %v", newUser.UserNum)
 	}
 
 	if newUser.Latitude != float {
diff --git a/main.go b/main.go
index fc4859ac..d342571d 100644
--- a/main.go
+++ b/main.go
@@ -430,7 +430,7 @@ func (s *DB) Raw(sql string, values ...interface{}) *DB {
 // Exec execute raw sql
 func (s *DB) Exec(sql string, values ...interface{}) *DB {
 	scope := s.NewScope(nil)
-	generatedSQL := scope.buildWhereCondition(map[string]interface{}{"query": sql, "args": values})
+	generatedSQL := scope.buildCondition(map[string]interface{}{"query": sql, "args": values}, true)
 	generatedSQL = strings.TrimSuffix(strings.TrimPrefix(generatedSQL, "("), ")")
 	scope.Raw(generatedSQL)
 	return scope.Exec().db
diff --git a/migration_test.go b/migration_test.go
index d58e1fb5..7c694485 100644
--- a/migration_test.go
+++ b/migration_test.go
@@ -7,6 +7,7 @@ import (
 	"fmt"
 	"os"
 	"reflect"
+	"strconv"
 	"testing"
 	"time"
 
@@ -168,6 +169,8 @@ type Num int64
 func (i *Num) Scan(src interface{}) error {
 	switch s := src.(type) {
 	case []byte:
+		n, _ := strconv.Atoi(string(s))
+		*i = Num(n)
 	case int64:
 		*i = Num(s)
 	default:
diff --git a/query_test.go b/query_test.go
index 77449f4f..3c3c74b5 100644
--- a/query_test.go
+++ b/query_test.go
@@ -99,7 +99,7 @@ func TestStringPrimaryKeyForNumericValueStartingWithZero(t *testing.T) {
 	var address AddressByZipCode
 	DB.First(&address, "00501")
 	if address.ZipCode != "00501" {
-		t.Errorf("Fetch a record from with a string primary key for a numeric value starting with zero should work, but failed")
+		t.Errorf("Fetch a record from with a string primary key for a numeric value starting with zero should work, but failed, zip code is %v", address.ZipCode)
 	}
 }
 
diff --git a/scope.go b/scope.go
index 762904d7..5ac147e4 100644
--- a/scope.go
+++ b/scope.go
@@ -8,7 +8,6 @@ import (
 	"fmt"
 	"reflect"
 	"regexp"
-	"strconv"
 	"strings"
 	"time"
 )
@@ -521,26 +520,58 @@ func (scope *Scope) primaryCondition(value interface{}) string {
 	return fmt.Sprintf("(%v.%v = %v)", scope.QuotedTableName(), scope.Quote(scope.PrimaryKey()), value)
 }
 
-func (scope *Scope) buildWhereCondition(clause map[string]interface{}) (str string) {
+func (scope *Scope) buildCondition(clause map[string]interface{}, include bool) (str string) {
+	var (
+		quotedTableName  = scope.QuotedTableName()
+		quotedPrimaryKey = scope.Quote(scope.PrimaryKey())
+		equalSQL         = "="
+		inSQL            = "IN"
+	)
+
+	// If building not conditions
+	if !include {
+		equalSQL = "<>"
+		inSQL = "NOT IN"
+	}
+
 	switch value := clause["query"].(type) {
-	case int, int8, int16, int32, int64, uint, uint8, uint16, uint32, uint64, sql.NullInt64:
-		return scope.primaryCondition(scope.AddToVars(value))
+	case sql.NullInt64:
+		return fmt.Sprintf("(%v.%v %s %v)", quotedTableName, quotedPrimaryKey, equalSQL, value.Int64)
+	case int, int8, int16, int32, int64, uint, uint8, uint16, uint32, uint64:
+		return fmt.Sprintf("(%v.%v %s %v)", quotedTableName, quotedPrimaryKey, equalSQL, value)
 	case []int, []int8, []int16, []int32, []int64, []uint, []uint8, []uint16, []uint32, []uint64, []string, []interface{}:
-		str = fmt.Sprintf("(%v.%v IN (?))", scope.QuotedTableName(), scope.Quote(scope.PrimaryKey()))
+		if !include && reflect.ValueOf(value).Len() == 0 {
+			return
+		}
+		str = fmt.Sprintf("(%v.%v %s (?))", quotedTableName, quotedPrimaryKey, inSQL)
 		clause["args"] = []interface{}{value}
 	case string:
 		if isNumberRegexp.MatchString(value) {
-			return scope.primaryCondition(scope.AddToVars(value))
-		} else if value != "" {
-			str = fmt.Sprintf("(%v)", value)
+			return fmt.Sprintf("(%v.%v %s %v)", quotedTableName, quotedPrimaryKey, equalSQL, scope.AddToVars(value))
+		}
+
+		if value != "" {
+			if !include {
+				if comparisonRegexp.MatchString(value) {
+					str = fmt.Sprintf("NOT (%v)", value)
+				} else {
+					str = fmt.Sprintf("(%v.%v NOT IN (?))", quotedTableName, scope.Quote(value))
+				}
+			} else {
+				str = fmt.Sprintf("(%v)", value)
+			}
 		}
 	case map[string]interface{}:
 		var sqls []string
 		for key, value := range value {
 			if value != nil {
-				sqls = append(sqls, fmt.Sprintf("(%v.%v = %v)", scope.QuotedTableName(), scope.Quote(key), scope.AddToVars(value)))
+				sqls = append(sqls, fmt.Sprintf("(%v.%v %s %v)", quotedTableName, scope.Quote(key), equalSQL, scope.AddToVars(value)))
 			} else {
-				sqls = append(sqls, fmt.Sprintf("(%v.%v IS NULL)", scope.QuotedTableName(), scope.Quote(key)))
+				if !include {
+					sqls = append(sqls, fmt.Sprintf("(%v.%v IS NOT NULL)", quotedTableName, scope.Quote(key)))
+				} else {
+					sqls = append(sqls, fmt.Sprintf("(%v.%v IS NULL)", quotedTableName, scope.Quote(key)))
+				}
 			}
 		}
 		return strings.Join(sqls, " AND ")
@@ -549,7 +580,7 @@ func (scope *Scope) buildWhereCondition(clause map[string]interface{}) (str stri
 		newScope := scope.New(value)
 		for _, field := range newScope.Fields() {
 			if !field.IsIgnored && !field.IsBlank {
-				sqls = append(sqls, fmt.Sprintf("(%v.%v = %v)", scope.QuotedTableName(), scope.Quote(field.DBName), scope.AddToVars(field.Field.Interface())))
+				sqls = append(sqls, fmt.Sprintf("(%v.%v %s %v)", quotedTableName, scope.Quote(field.DBName), equalSQL, scope.AddToVars(field.Field.Interface())))
 			}
 		}
 		return strings.Join(sqls, " AND ")
@@ -582,6 +613,7 @@ func (scope *Scope) buildWhereCondition(clause map[string]interface{}) (str stri
 
 			replacements = append(replacements, scope.AddToVars(arg))
 		}
+
 		if err != nil {
 			scope.Err(err)
 		}
@@ -603,98 +635,6 @@ func (scope *Scope) buildWhereCondition(clause map[string]interface{}) (str stri
 	return
 }
 
-func (scope *Scope) buildNotCondition(clause map[string]interface{}) (str string) {
-	var primaryKey = scope.PrimaryKey()
-
-	switch value := clause["query"].(type) {
-	case int, int8, int16, int32, int64, uint, uint8, uint16, uint32, uint64, sql.NullInt64:
-		return fmt.Sprintf("(%v.%v <> %v)", scope.QuotedTableName(), scope.Quote(primaryKey), value)
-	case []int, []int8, []int16, []int32, []int64, []uint, []uint8, []uint16, []uint32, []uint64, []string:
-		if reflect.ValueOf(value).Len() > 0 {
-			str = fmt.Sprintf("(%v.%v NOT IN (?))", scope.QuotedTableName(), scope.Quote(primaryKey))
-			clause["args"] = []interface{}{value}
-		} else {
-			return ""
-		}
-	case string:
-		if isNumberRegexp.MatchString(value) {
-			id, _ := strconv.Atoi(value)
-			return fmt.Sprintf("(%v.%v <> %v)", scope.QuotedTableName(), scope.Quote(primaryKey), id)
-		} else if comparisonRegexp.MatchString(value) {
-			str = fmt.Sprintf("NOT (%v)", value)
-		} else {
-			str = fmt.Sprintf("(%v.%v NOT IN (?))", scope.QuotedTableName(), scope.Quote(value))
-		}
-	case map[string]interface{}:
-		var sqls []string
-		for key, value := range value {
-			if value != nil {
-				sqls = append(sqls, fmt.Sprintf("(%v.%v <> %v)", scope.QuotedTableName(), scope.Quote(key), scope.AddToVars(value)))
-			} else {
-				sqls = append(sqls, fmt.Sprintf("(%v.%v IS NOT NULL)", scope.QuotedTableName(), scope.Quote(key)))
-			}
-		}
-		return strings.Join(sqls, " AND ")
-	case interface{}:
-		var sqls []string
-		var newScope = scope.New(value)
-		for _, field := range newScope.Fields() {
-			if !field.IsIgnored && !field.IsBlank {
-				sqls = append(sqls, fmt.Sprintf("(%v.%v <> %v)", scope.QuotedTableName(), scope.Quote(field.DBName), scope.AddToVars(field.Field.Interface())))
-			}
-		}
-		return strings.Join(sqls, " AND ")
-	}
-
-	replacements := []string{}
-	args := clause["args"].([]interface{})
-	for _, arg := range args {
-		var err error
-		switch reflect.ValueOf(arg).Kind() {
-		case reflect.Slice: // For where("id in (?)", []int64{1,2})
-			if scanner, ok := interface{}(arg).(driver.Valuer); ok {
-				arg, err = scanner.Value()
-				replacements = append(replacements, scope.AddToVars(arg))
-			} else if b, ok := arg.([]byte); ok {
-				replacements = append(replacements, scope.AddToVars(b))
-			} else if values := reflect.ValueOf(arg); values.Len() > 0 {
-				var tempMarks []string
-				for i := 0; i < values.Len(); i++ {
-					tempMarks = append(tempMarks, scope.AddToVars(values.Index(i).Interface()))
-				}
-				replacements = append(replacements, strings.Join(tempMarks, ","))
-			} else {
-				replacements = append(replacements, scope.AddToVars(Expr("NULL")))
-			}
-		default:
-			if scanner, ok := interface{}(arg).(driver.Valuer); ok {
-				arg, err = scanner.Value()
-			}
-
-			replacements = append(replacements, scope.AddToVars(arg))
-		}
-
-		if err != nil {
-			scope.Err(err)
-		}
-	}
-
-	buff := bytes.NewBuffer([]byte{})
-	i := 0
-
-	for pos := range str {
-		if str[pos] == '?' {
-			buff.WriteString(replacements[i])
-			i++
-		} else {
-			buff.WriteByte(str[pos])
-		}
-	}
-
-	str = buff.String()
-	return
-}
-
 func (scope *Scope) buildSelectQuery(clause map[string]interface{}) (str string) {
 	switch value := clause["query"].(type) {
 	case string:
@@ -758,19 +698,19 @@ func (scope *Scope) whereSQL() (sql string) {
 	}
 
 	for _, clause := range scope.Search.whereConditions {
-		if sql := scope.buildWhereCondition(clause); sql != "" {
+		if sql := scope.buildCondition(clause, true); sql != "" {
 			andConditions = append(andConditions, sql)
 		}
 	}
 
 	for _, clause := range scope.Search.orConditions {
-		if sql := scope.buildWhereCondition(clause); sql != "" {
+		if sql := scope.buildCondition(clause, true); sql != "" {
 			orConditions = append(orConditions, sql)
 		}
 	}
 
 	for _, clause := range scope.Search.notConditions {
-		if sql := scope.buildNotCondition(clause); sql != "" {
+		if sql := scope.buildCondition(clause, false); sql != "" {
 			andConditions = append(andConditions, sql)
 		}
 	}
@@ -844,7 +784,7 @@ func (scope *Scope) havingSQL() string {
 
 	var andConditions []string
 	for _, clause := range scope.Search.havingConditions {
-		if sql := scope.buildWhereCondition(clause); sql != "" {
+		if sql := scope.buildCondition(clause, true); sql != "" {
 			andConditions = append(andConditions, sql)
 		}
 	}
@@ -860,7 +800,7 @@ func (scope *Scope) havingSQL() string {
 func (scope *Scope) joinsSQL() string {
 	var joinConditions []string
 	for _, clause := range scope.Search.joinConditions {
-		if sql := scope.buildWhereCondition(clause); sql != "" {
+		if sql := scope.buildCondition(clause, true); sql != "" {
 			joinConditions = append(joinConditions, strings.TrimSuffix(strings.TrimPrefix(sql, "("), ")"))
 		}
 	}