ErrInvalidTransaction = errors.New("invalid transaction")
	// ErrNotImplemented not implemented
	ErrNotImplemented = errors.New("not implemented")
	// ErrMissingWhereClause missing where clause
	ErrMissingWhereClause = errors.New("WHERE conditions required")
	// ErrUnsupportedRelation unsupported relations
	ErrUnsupportedRelation = errors.New("unsupported relations")
	// ErrPrimaryKeyRequired primary keys required

			}},
			"SELECT * FROM `users` WHERE `users`.`id` = ? OR `name` <> ?",
			[]interface{}{"1", "jinzhu"},
		},
		{
			[]clause.Interface{clause.Select{}, clause.From{}, clause.Where{

		} else {
			expr.Build(builder)
		}
	}
}

// MergeClause merge where clauses
func (where Where) MergeClause(clause *Clause) {
	if w, ok := clause.Expression.(Where); ok {
		exprs := make([]Expression, len(w.Exprs)+len(where.Exprs))
		copy(exprs, w.Exprs)
		copy(exprs[len(w.Exprs):], where.Exprs)
		where.Exprs = exprs
	}

	clause.Expression = where
}

func And(exprs ...Expression) Expression {