标签：set trim order -- use now() 简单 ams HERE
1.Concat（）拼接
mysql> select * from pet; +----------+-------------+---------+------+------------+------------+ | name | owner | species | sex | birth | death | +----------+-------------+---------+------+------------+------------+ | Puffball | Diane | hamster | f | 2000-09-22 | NULL | | Cuihua | ZhouXingChi | DOG | M | 1999-09-21 | NULL | | DNN | Huimin | Cat | f | 2018-07-07 | NULL | | Claws | Gwen | cat | m | 1994-03-17 | NULL | | Buffy | Harold | dog | f | 1989-05-13 | NULL | | Fang | Benny | dog | m | 1909-08-27 | NULL | | Bowser | Diane | dog | m | 1979-08-31 | 1995-07-29 | | Chirpy | Gwen | bird | f | 1989-09-01 | NULL | | Slim | Benny | snake | m | 2006-04-21 | NULL | | Puffball | Diane | hamster | f | 2009-10-12 | NULL | +----------+-------------+---------+------+------------+------------+
拼接name与species列：
mysql> SELECT Concat(name,‘(‘,species,‘)‘) as info FROM pet order by name; +-------------------+ | info | +-------------------+ | Bowser(dog) | | Buffy(dog) | | Chirpy(bird) | | Claws(cat) | | Cuihua(DOG) | | DNN(Cat) | | Fang(dog) | | Puffball(hamster) | | Puffball(hamster) | | Slim(snake) | +-------------------+
2.SELECT简单测试
mysql> select 3*2; +-----+ | 3*2 | +-----+ | 6 | +-----+
Trim（）去空格：
mysql> select Rtrim(‘ abc‘); +---------------+ | Rtrim(‘ abc‘) | +---------------+ | abc | +---------------+
mysql> select now(); +---------------------+ | now() | +---------------------+ | 2020-04-25 09:33:10 | +---------------------+
mysql> SELECT name,upper(species) FROM pet order by name; +----------+----------------+ | name | upper(species) | +----------+----------------+ | Bowser | DOG | | Buffy | DOG | | Chirpy | BIRD | | Claws | CAT | | Cuihua | DOG | | DNN | CAT | | Fang | DOG | | Puffball | HAMSTER | | Puffball | HAMSTER | | Slim | SNAKE | +----------+----------------+
3.SOUNDEX（）：
mysql> select * from user; +----+-------+ | id | name | +----+-------+ | 1 | Lily | | 2 | Lily | | 3 | Y.Lee | +----+-------+
mysql> select id,name from user where name = ‘Y.Lie‘; Empty set (0.04 sec)
mysql> select id,name from user where soundex(name) = soundex(‘Y.Lie‘); +----+-------+ | id | name | +----+-------+ | 3 | Y.Lee | +----+-------+
4.Date（）：日期
mysql> SELECT birth FROM pet; +------------+ | birth | +------------+ | 2000-09-22 | | 1999-09-21 | | 2018-07-07 | | 1994-03-17 | | 1989-05-13 | | 1909-08-27 | | 1979-08-31 | | 1989-09-01 | | 2006-04-21 | | 2009-10-12 | +------------+
如果你想要的仅仅是日期，使用Date()是一个良好的习惯，即使你知道相应的列只包含日期也是如此。
这样，由于某种原因表中以后有日期和时间值，代码也不用改变，Time()在你只想用时间时使用它。
mysql> SELECT Date(birth) FROM pet; +-------------+ | Date(birth) | +-------------+ | 2000-09-22 | | 1999-09-21 | | 2018-07-07 | | 1994-03-17 | | 1989-05-13 | | 1909-08-27 | | 1979-08-31 | | 1989-09-01 | | 2006-04-21 | | 2009-10-12 | +-------------+
筛选：
mysql> select name,birth from pet where date(birth) between ‘1994-05-01‘ and ‘2018-09-30‘; +----------+------------+ | name | birth | +----------+------------+ | Puffball | 2000-09-22 | | Cuihua | 1999-09-21 | | DNN | 2018-07-07 | | Slim | 2006-04-21 | | Puffball | 2009-10-12 | +----------+------------+
mysql> select name,birth from pet where year(birth) between 1994 and 2018 -> and month(birth) between 5 and 9; +----------+------------+ | name | birth | +----------+------------+ | Puffball | 2000-09-22 | | Cuihua | 1999-09-21 | | DNN | 2018-07-07 | +----------+------------+
标签：set trim order -- use now() 简单 ams HERE
原文地址：https://www.cnblogs.com/direwolf22/p/12771744.html
