023 数据库学习笔记--修改字段非空+默认值 + 查询昨天数据比前一天数据温度高....

第一步：将字段为空的信息更改为默认值

第二步：更改字段为非空

第三步：设置默认值约束

update TableImageQuality set ImageScore= 0 where ImageScore is null
 ALTER TABLE TableImageQuality ALTER COLUMN ImageScore VARCHAR(10) not null 
 
update TableImageQuality set FilmScore= 0 where FilmScore is null
 ALTER TABLE TableImageQuality ALTER COLUMN FilmScore VARCHAR(10) not null 
 
 update TableImageQuality set DImageScore= 0 where DImageScore is null
 ALTER TABLE TableImageQuality ALTER COLUMN DImageScore VARCHAR(10) not null 
 
 update TableImageQuality set ReportScore= 0 where ReportScore is null
 ALTER TABLE TableImageQuality ALTER COLUMN ReportScore VARCHAR(10) not null 
 
 update TableImageQuality set AuditScore= 0 where AuditScore is null
 ALTER TABLE TableImageQuality ALTER COLUMN AuditScore VARCHAR(10) not null 
 
 update TableImageQuality set ApplicationScore= 0 where ApplicationScore is null
 ALTER TABLE TableImageQuality ALTER COLUMN ApplicationScore VARCHAR(10) not null 
 
alter table TableImageQuality add default (0) for ImageScore with values
alter table TableImageQuality add default (0) for FilmScore with values
alter table TableImageQuality add default (0) for DImageScore with values
alter table TableImageQuality add default (0) for ReportScore with values
alter table TableImageQuality add default (0) for AuditScore with values
alter table TableImageQuality add default (0) for ApplicationScore with values

查询昨天数据比前一天数据温度高....

SELECT *
FROM temperature_records t1
JOIN temperature_records t2 ON DATE_SUB(t1.date, INTERVAL 1 DAY) = t2.date
WHERE t1.temperature > t2.temperature;