echo print if else elseif switch case default while do for foreach break continue function return include require require_once include_once namespace use class interface trait extends implements public private protected static const global var isset empty unset array count in_array explode implode str_replace substr strlen trim json_encode json_decode header session_start select insert update delete from where group by order by having join inner join left join right join union distinct limit offset like between and or not in exists asc desc create table drop table alter table truncate index primary key foreign key auto_increment default null not null varchar int text date datetime timestamp time now() curdate() database table view procedure