Mysql-basic-2
This is my study note of MySql.Learning vedio link : 黑马程序员
Basic Part 2
table
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函数
Code
illustrate
CONTACT , LOWER , UPPER
拼接、小写、大写
LPAD,RPAD,SUBSTRING
左填充、右填充、截取字符串
CEIL,FLOOR,MOD,RAND,ROUND
向上取整、向下取整、求模、产生0-1随机数、保留小数
CURDATE,CURTIME,NOW
当前日期、当前时间、当前日前+时间
YEAR,MONTH,DAY,DATE_ADD,DATEDIFF
年、月、日、日期相加、日期相减
IF、IFNULL、CASE[…] WHEN…THEN… ELSE…END
判断、判断是否为空、CASE选择
For example12345678UPDATE tab SET id = LPAD(id,5,"0"); // 为工号长度不为5的工号前填补 ...
Mysql-basic-1
table
{
margin: auto;
}
This is my study note of MySql.Learning vedio link : 黑马程序员
Basic Part 1Basic structure
classify
name
illustrate
DDL
Data definition language
数据定义语言
DML
Data manipulation language
数据操作语言
DQL
Data query language
数据查询语言
DCL
Data contral language
数据控制语言
Data type
整型
img[alt="Alt text"]{
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img[alt="Alt text1"]{
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字符型
DDL(Data Definition Language)
Code
illustrate
SHOW DATABASEs
展示当前所有数据库
SELECT DATABA ...
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