Mysql如何按照日期对比数据

查询2011的数据：select * from 表 where year(date)='2011'

查找月份为12的数据：select * from 表 where month(date)='12'

查找天数为本年第二天的数据：select * from 表 where dayofyear(date)='2'

我解释一下：

select * from 表 where 这是必须的

year,month,dayofyear是mysql的函数，分别是取得年，月，和当前时间在本年是第几天的3个函数

date就是你保存时间的字段

等号后面的当然条件啦。

如何比较2个mysql数据库数据

sql语句：因为MySQL 没有full outer join,所以用left join union all right join来实现

select a.table_schema,

a.table_name,

a.column_name,

b.table_schema,

b.table_name,

b.column_name

from information_schema.columns a

left join information_schema.columns b on a.table_name = b.table_name and a.column_name =

b.column_name andb.table_schema = 'DBNAMe1'

where a.table_schema = 'DBNAME2' and

(b.table_name is null or

b.column_name is null)

union all

select a.table_schema,

a.table_name,

a.column_name,

b.table_schema,

b.table_name,

b.column_name

from information_schema.columns a

left join information_schema.columns b on a.table_name = b.table_name and a.column_name =

b.column_name andb.table_schema = 'DBNAME2'

where a.table_schema = 'DBNAME1' and

(b.table_name is null or

b.column_name is NULL)

   SELECT a.date_3 - b.date_3 FROM tab1 a,tab2 b WHERE b.numb = a.numb

前提是tab1和tab2都要有对应的numb

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