下面是一个示例的SQL查询语句,假设我们有一个表名为table_name,其中有一个名为date_column的日期字段,我们要查询日期字段为2022-01-01和2022-01-02的记录: SELECT*FROMtable_nameWHEREdate_columnIN('2022-01-01','2022-01-02'); 1. 2. 3. 执行SQL查询语句 最后,将编写好的查询语句在MySQL数据库中执行,...
EXPLAIN SELECT SQL_NO_CACHE * FROM `type` LEFT JOIN book ON type.card = book.card; # 情况2:内连接 DROP INDEX X ON `type`; EXPLAIN SELECT SQL_NO_CACHE * FROM `type` INNER JOIN book ON type.card = book.card; #添加索引 CREATE INDEX Y ON book(card); EXPLAIN SELECT SQL_NO_CACHE...
TheDATEtype is used for values with a date part but no time part. MySQL retrieves and displaysDATEvalues in'_`YYYY-MM-DD`_'format. The supported range is'1000-01-01'to'9999-12-31'. Date"类型用于包含日期部分但不包含时间部分的值。MySQL 以'_`YYY-MM-DD`_'格式检索和显示DATE值。支持的...
Date: December 23, 2009 01:29AM Hi, I have two tables whose DDLs are: test_datetime: CREATE TABLE `test_datetime` ( `if_id` int(10) unsigned NOT NULL, `coll_type_id` tinyint(3) unsigned NOT NULL, `value_diff` bigint(20) unsigned DEFAULT NULL, ...
2、NO_ZERO_IN_DATE 模式:日期中年、月或日不允许为0,如不允许'2021-00-01', '2021-01-00',启用此模式后,MySQL会阻止插入或更新包含这种零值的日期数据。 date, datetime, timestamp都会受这两个SQL MODE的影响,而且它们需要跟 STRICT MODE 一起使用。启用 STRICT MODE 将在遇到数据不符合规范的情况下引发...
lsis aliased to `ls --color=tty' [root@localhost ~]# type cd cd is a shellbuiltin [root@localhost~]# type date dateis /bin/date [root@localhost~]# type mysql mysqlis /usr/bin/mysql [root@localhost~]# type nginx -bash:type: nginx: not found ...
For additional information aboutYEARdisplay format and interpretation of input values, seeSection 13.2.4, “The YEAR Type”. Note TheYEAR(4)data type with an explicit display width is deprecated; you should expect support for it to be removed in a future version of MySQL. Instead, useYEARwith...
If the value falls out of the supported range of the TIMESTAMP type when converted from from_tz to UTC, no conversion occurs. The TIMESTAMP range is described in Section 11.2.1, “Date and Time Data Type Syntax”. mysql> SELECT CONVERT_TZ('2004-01-01 12:00:00','GMT','MET'); ...
1 row in set (0.00 sec) mysql> 返回UTC日期的函数 utc_date()函数返回当前utc(世界标准时间)日期值,其格式为yyyy-mm-dd或者yyyymmdd; mysql> select utc_date(), utc_date()+0; +---+---+ | utc_date() | utc_date()+0 | +---+---+ | 2022-07-12 ...
随着数据库的发展, 数据库DAO层框架也蓬勃发展. 从一开始的JDBC, 到Mybaties与Mybaties plus, 再到SpringData. 持久层框架一直在发展, 这种良性的发展更加推动程序员专注业务方面的发展, 而不是花费过多的经历去编写基本的DAO操作. 在最近的项目中使用了mybatis-plus框架,这个框架自动生成映射文件的工具会将MySQL中...