// MergeClause merge order by clauses
func (returning Returning) MergeClause(clause *Clause) {
	if v, ok := clause.Expression.(Returning); ok && len(returning.Columns) > 0 {
		if v.Columns != nil {
			returning.Columns = append(v.Columns, returning.Columns...)
		} else {
			returning.Columns = nil
		}
	}
	clause.Expression = returning

			if stmt.Schema != nil && len(values.Columns) >= 1 {
				selectColumns, restricted := stmt.SelectAndOmitColumns(true, true)

				columns := make([]string, 0, len(values.Columns)-1)
				for _, column := range values.Columns {
					if field := stmt.Schema.LookUpField(column.Name); field != nil {
						if v, ok := selectColumns[field.DBName]; (ok && v) || (!ok && !restricted) {

					clauseSelect.Columns[idx] = clause.Column{Name: name, Raw: true}
				} else if f := db.Statement.Schema.LookUpField(name); f != nil {
					clauseSelect.Columns[idx] = clause.Column{Name: f.DBName}
				} else {
					clauseSelect.Columns[idx] = clause.Column{Name: name, Raw: true}
				}
			}
		} else if db.Statement.Schema != nil && len(db.Statement.Omits) > 0 {

				matchedFieldCount := make(map[string]int, len(columns))
				for idx, column := range columns {
					if field := sch.LookUpField(column); field != nil && field.Readable {
						fields[idx] = field
						if count, ok := matchedFieldCount[column]; ok {
							// handle duplicate fields
							for _, selectField := range sch.Fields {
								if selectField.DBName == column && selectField.Readable {
									if count == 0 {

				"name": "my name",
			},
			expect: clause.Values{
				Columns: []clause.Column{{Name: "name"}},
				Values:  [][]interface{}{{"my name"}},
			},
		},
		{
			name: "Test convert int value",
			input: map[string]interface{}{
				"age": 18,
			},
			expect: clause.Values{
				Columns: []clause.Column{{Name: "age"}},
				Values:  [][]interface{}{{18}},
			},
		},
		{

			"SELECT * FROM `users`", nil,
		},
		{
			[]clause.Interface{clause.Select{
				Columns: []clause.Column{clause.PrimaryColumn},
			}, clause.From{}},
			"SELECT `users`.`id` FROM `users`", nil,
		},
		{
			[]clause.Interface{clause.Select{
				Columns: []clause.Column{clause.PrimaryColumn},
			}, clause.Select{
				Columns: []clause.Column{{Name: "name"}},
			}, clause.From{}},
			"SELECT `name` FROM `users`", nil,
		},
		{

	q.db.Where(query, args...)
	return q
}

func (q *joinBuilder) Select(columns ...string) JoinBuilder {
	q.db.Select(columns)
	return q
}

func (q *joinBuilder) Omit(columns ...string) JoinBuilder {
	q.db.Omit(columns...)
	return q
}

type preloadBuilder struct {
	limitPerRecord int
	db             *DB
}

		builder.WriteByte(' ')
	} else {
		if len(onConflict.Columns) > 0 {
			builder.WriteByte('(')
			for idx, column := range onConflict.Columns {
				if idx > 0 {
					builder.WriteByte(',')
				}
				builder.WriteQuoted(column)
			}
			builder.WriteString(`) `)
		}

		if len(onConflict.TargetWhere.Exprs) > 0 {
			builder.WriteString(" WHERE ")
			onConflict.TargetWhere.Build(builder)

func (db *DB) Omit(columns ...string) (tx *DB) {
	tx = db.getInstance()

	if len(columns) == 1 && strings.ContainsRune(columns[0], ',') {
		tx.Statement.Omits = strings.FieldsFunc(columns[0], utils.IsValidDBNameChar)
	} else {
		tx.Statement.Omits = columns
	}
	return
}

func (idx Index) Table() string {
	return idx.TableName
}

// Name return the name of the index.
func (idx Index) Name() string {
	return idx.NameValue
}

// Columns return the columns of the index
func (idx Index) Columns() []string {
	return idx.ColumnList
}

// PrimaryKey returns the index is primary key or not.
func (idx Index) PrimaryKey() (isPrimaryKey bool, ok bool) {