1.聚合函数:
select * from user where concat(use,addr) like "%"#{name}"%";
1.count() count(字段)忽略所有null count(*) 不忽略null count(1) 不忽略null 2.sum() 3.avg() 4.max() 5.mix()
SELECT [ALL | DISTINCT] {* | table.* | [table.field1[as alias1][,table.field2[as alias2]][,...]]} FROM table_name [as table_alias] [left | right | inner join table_name2] #联合查询 [WHERE ...] #指定结果需满足的条件 [GROUP BY ...] #指定结果按照哪几个字段来分组 [HAVING] #过滤分组的记录必须满足的次要条件 [ORDER BY ...] #指定查询记录按一个或多个条件排序 [LIMIT {[offset,]row_count | row_countOFFSET offset}]; # 指定查询的记录从哪条至哪条
修改加密: update 表名 set password=MD5(password) where id=1; update 表名 set password=MD5(password) ; 插入加密: insert into 表名(id,user,pwd) value('1','ooo',MD5('1234')); 查询加密: select *from user where user='xiaoming' and pwd=MD5('123456');