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Mysql cheetsheet

Mysql cheetsheet

作者: 万年场保安 | 来源:发表于2019-12-26 14:38 被阅读0次

    记录一下,方便查阅

    Connect/Disconnect

    mysql -h <host> -u <user> -p<passwd>
    mysql -h <host> -u <user> -p
    Enter password: ********
    mysql -u user -p
    mysql
    mysql -h <host> -u <user> -p <Database>
    

    Query

     SELECT * FROM table
     SELECT * FROM table1, table2, ...
     SELECT field1, field2, ... FROM table1, table2, ...
     SELECT ... FROM ... WHERE condition
     SELECT ... FROM ... WHERE condition GROUP BY field
     SELECT ... FROM ... WHERE condition GROUP BY field HAVING condition2
     SELECT ... FROM ... WHERE condition ORDER BY field1, field2
     SELECT ... FROM ... WHERE condition ORDER BY field1, field2 DESC
     SELECT ... FROM ... WHERE condition LIMIT 10
     SELECT DISTINCT field1 FROM ...
     SELECT DISTINCT field1, field2 FROM ...
    
     SELECT ... FROM t1 JOIN t2 ON t1.id1 = t2.id2 WHERE condition
     SELECT ... FROM t1 LEFT JOIN t2 ON t1.id1 = t2.id2 WHERE condition
     SELECT ... FROM t1 JOIN (t2 JOIN t3 ON ...) ON ...
     SELECT ... FROM t1 JOIN t2 USING(id) WHERE condition
      -- 正则查询(RLIKE|REGEXP)
     SELECT * FROM table WHERE column REGEXP '^(A|B|C)'
     SELECT * FROM table WHERE rec RLIKE "^b$";  
     -- 获得表或者行信息
     DESCRIBE table [column]
     
     --日期时间
     SELECT CURRENT_DATE, (YEAR(CURRENT_DATE)­YEAR(date_col)) AS time_diff [FROM table]; 
    

    Conditionals

     field1 = value1
     field1 <> value1
     field1 LIKE 'value _ %'
     field1 IS NULL
     field1 IS NOT NULL
     field1 IN (value1, value2)
     field1 NOT IN (value1, value2)
     condition1 AND condition2
     condition1 OR condition2
    

    table Index

    CREATE [UNIQUE|FULLTEXT] INDEX index_name ON table (column,...)
    DROP INDEX index_name
    

    Data Manipulation

     INSERT INTO table1 (field1, field2, ...) VALUES (value1, value2, ...)
     INSERT table1 SET field1=value_1, field2=value_2 ...
    
     LOAD DATA INFILE '/tmp/mydata.txt' INTO TABLE table1
     FIELDS TERMINATED BY ',' OPTIONALLY ENCLOSED BY '"' ESCAPED BY '\\'
    
     DELETE FROM table1 / TRUNCATE table1
     DELETE FROM table1 WHERE condition
     -- join:
     DELETE FROM table1, table2 WHERE table1.id1 = table2.id2 AND condition
    
     UPDATE table1 SET field1=new_value1 WHERE condition
     -- join:
     UPDATE table1, table2 SET field1=new_value1, field2=new_value2, ...
     WHERE table1.id1 = table2.id2 AND condition
    

    Browsing

     SHOW DATABASES
     SHOW TABLES
     SHOW FIELDS FROM table
     -- 几种查询表信息方法
     SHOW COLUMNS FROM table 
     DESCRIBE table 
     DESC table 
     EXPLAIN table
     
     SHOW CREATE TABLE table
     SHOW CREATE TRIGGER trigger
     SHOW TRIGGERS LIKE '%update%'
     SHOW PROCESSLIST
     KILL process_number
     SELECT table_name, table_rows FROM INFORMATION_SCHEMA.TABLES WHERE TABLE_SCHEMA = '**yourdbname**';
     
     mysqlshow
     mysqlshow database
     
     SELECT current_database()
    

    Create / delete / select / alter database

    CREATE DATABASE [IF NOT EXISTS] mabase [CHARACTER SET charset] [COLLATE collation]
    CREATE DATABASE mabase CHARACTER SET utf8
    DROP DATABASE mabase
    USE mabase

    ALTER DATABASE mabase CHARACTER SET utf8

    Create table
    CREATE TABLE table (field1 type1, field2 type2, ...)
     CREATE TABLE table (field1 type1 unsigned not null auto_increment, field2 type2, ...)
     CREATE TABLE table (field1 type1, field2 type2, ..., INDEX (field))
     CREATE TABLE table (field1 type1, field2 type2, ..., PRIMARY KEY (field1))
     CREATE TABLE table (field1 type1, field2 type2, ..., PRIMARY KEY (field1, field2))
     CREATE TABLE table1 (fk_field1 type1, field2 type2, ...,
       FOREIGN KEY (fk_field1) REFERENCES table2 (t2_fieldA)
         [ON UPDATE] [CASCADE|SET NULL|RESTRICT]
         [ON DELETE] [CASCADE|SET NULL|RESTRICT])
     CREATE TABLE table1 (fk_field1 type1, fk_field2 type2, ...,
       FOREIGN KEY (fk_field1, fk_field2) REFERENCES table2 (t2_fieldA, t2_fieldB))
     CREATE TABLE table IF NOT EXISTS (...)
    
     CREATE TABLE new_tbl_name LIKE tbl_name
       [SELECT ... FROM tbl_name ...]
    
     CREATE TEMPORARY TABLE table (...)
    
     CREATE table new_table_name as SELECT [ *|column1, column2 ] FROM table_name
    

    delete table

    DROP TABLE table
     DROP TABLE IF EXISTS table
     DROP TABLE table1, table2, ...
     DROP TEMPORARY TABLE table
    

    modify table

     ALTER TABLE table MODIFY field1 type1 
     ALTER TABLE table MODIFY field1 type1 NOT NULL ... 
     ALTER TABLE table CHANGE old_name_field1 new_name_field1 type1
     ALTER TABLE table CHANGE old_name_field1 new_name_field1 type1 NOT NULL ...
     ALTER TABLE table ALTER field1 SET DEFAULT ...
     ALTER TABLE table ALTER field1 DROP DEFAULT
     ALTER TABLE table ADD new_name_field1 type1
     ALTER TABLE table ADD new_name_field1 type1 FIRST
     ALTER TABLE table ADD new_name_field1 type1 AFTER another_field
     ALTER TABLE table DROP field1
     ALTER TABLE table ADD INDEX (field);
     ALTER TABLE table ADD PRIMARY KEY (field);
    
     -- Change field order:
     ALTER TABLE table MODIFY field1 type1 FIRST
     ALTER TABLE table MODIFY field1 type1 AFTER another_field
     ALTER TABLE table CHANGE old_name_field1 new_name_field1 type1 FIRST
     ALTER TABLE table CHANGE old_name_field1 new_name_field1 type1 AFTER another_field
    
     ALTER TABLE old_name RENAME new_name;
    

    Keys

    CREATE TABLE table (..., PRIMARY KEY (field1, field2))
    CREATE TABLE table (..., FOREIGN KEY (field1, field2) REFERENCES table2 (t2_field1, t2_field2))
    ALTER TABLE table ADD PRIMARY KEY (field);
    ALTER TABLE table ADD CONSTRAINT constraint_name PRIMARY KEY (field, field2);

    create/modify/drop view

    CREATE VIEW view AS SELECT ... FROM table WHERE ...

    Privileges

    CREATE USER 'user'@'localhost' IDENTIFIED BY 'password';

    GRANT ALL PRIVILEGES ON base.* TO 'user'@'localhost' IDENTIFIED BY 'password';
    GRANT SELECT, INSERT, DELETE ON base.* TO 'user'@'localhost' IDENTIFIED BY 'password';
    REVOKE ALL PRIVILEGES ON base.* FROM 'user'@'host'; -- one permission only
    REVOKE ALL PRIVILEGES, GRANT OPTION FROM 'user'@'host'; -- all permissions

    SET PASSWORD = PASSWORD('new_pass')
    SET PASSWORD FOR 'user'@'host' = PASSWORD('new_pass')
    SET PASSWORD = OLD_PASSWORD('new_pass')

    DROP USER 'user'@'host'

    Main data types

    TINYINT (1o: -127+128)
    SMALLINT (2o: +-65 000)
    MEDIUMINT (3o: +-16 000 000)
    INT (4o: +-2 000 000 000)
    BIGINT (8o: +-9.10^18)
    Precise interval: -(2^(8N-1)) -> (2^8N)-1
    /!\ INT(2) = "2 digits displayed" -- NOT "number with 2 digits max"
    INT NOT NULL auto_increment PRIMARY KEY -- auto-counter for PK
    FLOAT(M,D) DOUBLE(M,D) FLOAT(D=0->53)
    /!\ 8,3 -> 12345,678 -- NOT 12345678,123!
    TIME (HH:MM) YEAR (AAAA) DATE (AAAA-MM-JJ) DATETIME (AAAA-MM-JJ HH:MM; années 1000->9999)
    TIMESTAMP (like DATETIME, but 1970->2038, compatible with Unix)
    VARCHAR (single-line; explicit size)
    TEXT (multi-lines; max size=65535)
    BLOB (binary; max size=65535)
    Variants for TEXT&BLOB: TINY (max=255) MEDIUM (max=~16000) LONG (max=4Go)
    Ex: VARCHAR(32), TINYTEXT, LONGBLOB, MEDIUMTEXT
    ENUM ('value1', 'value2', ...) -- (default NULL, or '' if NOT NULL)
    Forgot root password?
    /etc/init.d/mysql stop mysqld_safe --skip-grant-tables &
    $ mysql # on another terminal
    mysql > UPDATE mysql.user SET password=PASSWORD('nouveau') WHERE user='root';

    Kill mysqld_safe from the terminal, using Control + \

    $ /etc/init.d/mysql start
    Repair tables after unclean shutdown
    mysqlcheck --all-databases
    mysqlcheck --all-databases --fast

    Loading data

    mysql> SOURCE input_file
    mysql -uroot database < filename-20120201.sql

    cat filename-20120201.sql | mysql database

    mysqldump -u [username] -p [database] > data_backup.sql;

    -- Load tab­delimited data into a table (Use \n f or NULL)
    LOAD DATA LOCAL INFILE "infile.txt" INTO TABLE table_name;

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