mysql 常用語句

增加字段和索引

ALTER TABLE `table_name` ADD `order` tinyint(3) unsigned NOT NULL DEFAULT '0' COMMENT '排序';
ALTER TABLE `table_name` ADD INDEX order ( `order` );

刪除索引和字段

drop index index_name  on table_name;

alter table table_name  DROP COLUMN   field_name;

判斷結束和開始時間是否有重合
( 
({$data['begin_time']} BETWEEN begin_time AND end_time) or 
({$data['end_time']} BETWEEN begin_time AND end_time) or 
( begin_time>={$data['begin_time']} and end_time<={$data['end_time']})
 )

修改如果沒有則添加

insert into table(fields)
(SELECT fields FROM table2 where id=xxx)
on duplicate key
UPDATE field=field (field)