MySQL

文章目录

1. 基本命令

mysql

基本命令

• SHOW DATABASES;

• SHOW TABLES;

• USE DATABASE

• CREATE DATABASE db_name

• DROP DATABASE db_name

• DESC table

• SHOW CREATE TABLE table

• DROP TABLE table

• ALTER TABLE table ADD COLUMN col VARCHAR(10) NOT NULL

• CHANGE COLUMN

• DROP COLUMN

• SELECT *
  FROM table
  WHERE condition
  ORDER BY name DESC
  LIMIT num OFFSET skip_num

• SELECT COUNT(*) num
  FROM table
  GROUP BY name;

• AVG(column)

• SUM()

• MAX()

• MIN()

• SELECT *
  FROM table1, table2

• alias
  SELECT
  s.id sid
  s.name
  s.gender
  c.id cid
  c.name cname
  FROM students s, classes c;

• SELECT
  s.id
  s.class_id
  c.name class_name
  FROM students s
  INNER JOIN classes c
  ON s.class_id = c.id;

• RIGHT OUTER JOIN 右表溢出

• LEFT OUTER JOIN

• FULL OUTER JOIN

• INSERT
  INSERT INTO table (col1, col2) VALUES (val1, val2), (val3, val4);

• UPDATE
  UPDATE table SET col1=val1, col2=val2 WHERE condition;

• DELETE
  DELETE FROM table WHERE condition

• REPLACE INTO

• INSERT IGNORE INTO

• INSERT INTO …… ON DUPLIOCATE KEY UPDATE col1=val1, col2=val2;