/sql

学习sql

Primary LanguageTSQLMIT LicenseMIT

sql

env

# macos
$ mysql
Welcome to the MySQL monitor.  Commands end with ; or \g.
Your MySQL connection id is 7
Server version: 8.0.16 MySQL Community Server - GPL
...
> show databases
> use [db name]
> show tables
> desc [table name]
> SELECT * FROM [table name]

数据过滤

  • 比较运算符
    • > < >= != !>
    • BETWEEN
    • IS NULL
  • 逻辑运算符
    • AND OR IN NOT
  • 通配符
    • LIKE % *

SQL函数

  • 算术函数
    • ABS MOD ROUND
  • 字符串函数
    • CONCAT LENGTH CHAR_LENGTH LOWER UPPER REPLACE SUBSTRING
  • 日期函数
    • CURRENT_DATE CURRENT_TIME CURRENT_TIMESTAMP EXTRACT DATE YEAR MONTH DAY HOUR MINUTE SECOND
  • 转换函数
    • CAST COALESCE
  • 聚集函数
    • COUNT MAX MIN SUM AVG