mysql

条件

if

WHERE IF(条件, true执行条件, false执行条件 )

SELECT * FROM  book WHERE IF(price > 120,  btypeid=10,  btypeid=11);

case when

SELECTpp_.id,pp_.project_name 
FROMpv_project pp_CASE 1WHEN trueTHEN1 = 1ELSEpp_.project_name = 'bbbbb'
END 

日期相关

1.mysql查询当天的数据

select * from table where to_days(时间字段) = to_days(now());

2.mysql查询昨天的数据

select * from table where to_days(now( ) ) - to_days( 时间字段名) = 1  

3.mysql查询近一周的数据

SELECT * FROM table WHERE date(时间字段) >= DATE_SUB(CURDATE(),INTERVAL 7 DAY)

4.mysql查询近一个月的数据

SELECT * FROM table WHERE date(时间字段) >= DATE_SUB(CURDATE(),INTERVAL 1 MONTH)

5.mysql查询本月的数据

select * from table where DATE_FORMAT(时间字段, '%Y%m' ) = DATE_FORMAT( CURDATE( ) , '%Y%m' ) 

6.mysql查询上月的数据

select * from table where PERIOD_DIFF(date_format(now(),'%Y%m') , date_format(时间字段,'%Y%m')) =1

7.mysql查询本年的数据

select * from table where YEAR(时间字段)=YEAR(now());  

8.mysql查询上一年的数据

select * from table where year(时间字段)=year(date_sub(now(),interval 1 year));  

9.mysql查询本周数据（周一为第一天）

SELECT * FROM table WHERE YEARWEEK(date_format(时间字段,'%Y-%m-%d'),1) = YEARWEEK(now(),1);

10.mysql查询近五分钟的数据

SELECT * FROM table WHERE 时间字段 >= DATE_SUB(now(),INTERVAL 5 MINUTE)

11 过去的12个月

SELECTmon.`month`,IFNULL( tmp.countDelayComplete, 0 ) AS countDelayComplete,IFNULL( tmp.countDelayUnComplete, 0 ) AS countDelayUnComplete,IFNULL( tmp.rate, 0 ) AS rate 
FROM(SELECTDATE_FORMAT( CURDATE(), '%Y.%m' ) AS `month` UNIONSELECTDATE_FORMAT(( CURDATE() - INTERVAL 1 MONTH ), '%Y.%m' ) AS `month` UNIONSELECTDATE_FORMAT(( CURDATE() - INTERVAL 2 MONTH ), '%Y.%m' ) AS `month` UNIONSELECTDATE_FORMAT(( CURDATE() - INTERVAL 3 MONTH ), '%Y.%m' ) AS `month` UNIONSELECTDATE_FORMAT(( CURDATE() - INTERVAL 4 MONTH ), '%Y.%m' ) AS `month` UNIONSELECTDATE_FORMAT(( CURDATE() - INTERVAL 5 MONTH ), '%Y.%m' ) AS `month` UNIONSELECTDATE_FORMAT(( CURDATE() - INTERVAL 6 MONTH ), '%Y.%m' ) AS `month` UNIONSELECTDATE_FORMAT(( CURDATE() - INTERVAL 7 MONTH ), '%Y.%m' ) AS `month` UNIONSELECTDATE_FORMAT(( CURDATE() - INTERVAL 8 MONTH ), '%Y.%m' ) AS `month` UNIONSELECTDATE_FORMAT(( CURDATE() - INTERVAL 9 MONTH ), '%Y.%m' ) AS `month` UNIONSELECTDATE_FORMAT(( CURDATE() - INTERVAL 10 MONTH ), '%Y.%m' ) AS `month` UNIONSELECTDATE_FORMAT(( CURDATE() - INTERVAL 11 MONTH ), '%Y.%m' ) AS `month` ) AS monLEFT JOIN (SELECTdate_format( pvr.plan_completion_time, '%Y.%m' ) AS MONTH)

格式化

SELECT date_format( createTime,'%Y-%m-%d') AS createTime 

日期差值

TIMESTAMPDIFF(DAY, pr_.plan_completion_time, NOW()),SELECT TIMESTAMPDIFF(DAY,'1993-03-23 00:00:00',DATE_FORMAT(NOW(), '%Y-%m-%d %H:%i:%S'))SELECT DATEDIFF('2018-12-01 12:23:59','2018-11-03 12:23:59') FROM DUAL;

类型可选

MICROSECOND
SECOND
MINUTE
HOUR
DAY
WEEK
MONTH
QUARTER
YEAR

示例

SELECTpp_.id AS project_id,pr_.report_num,CONCAT(TIMESTAMPDIFF( DAY, NOW(), pr_.plan_completion_time ),'天',ABS( TIMESTAMPDIFF( HOUR, NOW(), pr_.plan_completion_time ) % 24 ),'时',ABS( TIMESTAMPDIFF( MINUTE, NOW(), pr_.plan_completion_time ) % 60  ),'分' ) AS date,pp_.project_name,pwf_.work_flow_name,pr_.receive_report_time,JSON_UNQUOTE(json_extract( form_data, '$."117"' )) AS '117',JSON_UNQUOTE(json_extract( form_data, '$."155"' )) AS '155',JSON_UNQUOTE(json_extract( form_data, '$."158"' )) AS '158',JSON_UNQUOTE(json_extract( form_data, '$."162"' )) AS '162',JSON_UNQUOTE(json_extract( form_data, '$."163"' )) AS '163',JSON_UNQUOTE(json_extract( form_data, '$."165"' )) AS '165',JSON_UNQUOTE(json_extract( form_data, '$."169"' )) AS '169',JSON_UNQUOTE(json_extract( form_data, '$."175"' )) AS '175',JSON_UNQUOTE(json_extract( form_data, '$."176"' )) AS '176',JSON_UNQUOTE(json_extract( form_data, '$."142"' )) AS '142',JSON_UNQUOTE(json_extract( form_data, '$."145"' )) AS '145',pr_.plan_completion_time,
CASEpr_.STATUS WHEN 'not_finish' THEN'未完成' WHEN 'finish' THEN'已完成' ELSE '延期完成' END AS STATUS,
CASEpr_.is_delay WHEN 0 THEN'即将延期' ELSE '已延期' END AS is_delay 
FROMplm.pv_report pr_LEFT JOIN plm.pv_project pp_ ON pr_.project_id = pp_.idLEFT JOIN plm.pv_project_work_flow pwf_ ON pr_.work_flow_id = pwf_.idLEFT JOIN plm.pv_report_form_data prfd_ ON pr_.id = prfd_.report_id

count

条件count

select count(age <  19 or null) from sys_userselect count(if(age <  19, 1, null)) from sys_user // 返回 1条数据
select count(case when age <  19 then 1 end) from sys_user // 返回 1条数据

位数

一、FORMAT（四舍五入）SELECT FORMAT(4.4289, 2)二、ROUND（四舍五入）SELECT ROUND(4.4289, 2)
三、TRUNCATE（直接舍去）TRUNCATE（X,D）函数会将小数部分2位以后的值直接舍去SELECT TRUNCATE(4.4289, 2)
四、CONVERT（四舍五入）SELECT CONVERT(4.4289,DECIMAL(10,2));
五、CAST（四舍五入）SELECT CAST(4.4289 as DECIMAL(10,2));

分组

字符串拼接

效果： 何庆青,史小辉,蒋铁荣

group_concat( pvcu_.user_name SEPARATOR ‘,’ )

SELECTpvp_.erp_id,pvp_.program_code,pvp_.project_name,group_concat( pvcu_.user_name SEPARATOR ',' ) AS pm 
FROMpv_project pvp_LEFT JOIN pv_project_csp_user pvcu_ ON pvp_.csp_id = pvcu_.csp_id 
GROUP BYpvp_.id

case when

CASE case_valueWHEN when_value THENstatement_listELSEstatement_list
END CASE;示例SELECTppp_.id,ppcu_.user_id,ppcu_.user_name,ppcu_.email,
CASEppcu_.enabled WHEN 1 THEN'正常' ELSE '禁用' 
END AS STATUS 
FROMplm.pv_project ppp_LEFT JOIN pv_project_user ppu_ ON ppp_.id = ppu_.project_idLEFT JOIN pv_project_csp_user ppcu_ ON ppu_.user_id = ppcu_.user_id AND ppp_.csp_id = ppcu_.csp_id

  1、简单函数 CASE [col_name] WHEN [value1] THEN [result1]…ELSE [default] END2、搜索函数 CASE WHEN [expr] THEN [result1]…ELSE [default] END

JSON处理

insert into userinfo (id, info) values (3,'{"a": 1, "b": 2, "c": {"d": 4},"d":[1,2,3],"e":{"name":"tom","age":12}}');取出元素select json_extract(info,'$.a') from userinfo where id=3; # 1
select json_extract(info,'$.c.d') from userinfo where id=3; # 4
select json_extract(info,'$.d') from userinfo where id=3; # [1,2,3]
select json_extract(info,'$.d[0]') from userinfo where id=3; # 1
select json_extract(info,'$.d[3]') from userinfo where id=3; # NULL

字符串

SELECT CONCAT(字段1,字段2,字段3,...) from 表名;

数学函数

取整 取余

SELECT 10 DIV 3; -- 返回结果为 3SELECT 10 / / 3; -- 返回结果为 3SELECT MOD(10, 3); -- 返回结果为 1SELECT 10 % 3; -- 返回结果为 1