[Database] common queries -MySql

1, two tables compare the difference fields

db1: a database;

db2: 2 data blocks;

tb1: db1 and db2 common name for the database.

SELECT
	*
FROM
	information_schema.`COLUMNS`
WHERE
	TABLE_SCHEMA IN ('db1', 'db2')
AND
	TABLE_NAME = 'tb1' ORDER BY COLUMN_NAME

2, the date to the current date data update

UPDATE tb1
SET time1 = CONCAT(
	DATE_FORMAT(NOW(), '%Y-%m-%d'),
	DATE_FORMAT(time1, ' %H:%i:%S')
),
 time2 = CONCAT(
	DATE_FORMAT(NOW(), '%Y-%m-%d'),
	DATE_FORMAT(time2,' %H:%i:%S')
)
LIMIT 520;

3, clear all data tables

db1: database name

SELECT
	CONCAT("DELETE FROM db1.`",TABLE_NAME,"`;")
FROM
	information_schema.`TABLES`
WHERE
	TABLE_SCHEMA = 'db1'
AND
	TABLE_TYPE = 'BASE TABLE';

4, delete all the tables

db1: database name

SELECT 
    CONCAT("DROP TABLE `",TABLE_NAME,"`;") 
FROM 
    information_schema.`TABLES` 
WHERE 
    TABLE_TYPE = "BASE TABLE" 
AND 
    TABLE_SCHEMA = "db1";

5, delete all views

db1: database name

SELECT 
    CONCAT("DROP VIEW `",TABLE_NAME,"`;")  
FROM 
    information_schema.`TABLES` 
WHERE 
    TABLE_TYPE = "VIEW" 
AND 
    TABLE_SCHEMA = "db1";

6, delete all functions

db1: database name

SELECT 
    CONCAT("DROP FUNCTION `",ROUTINE_NAME,"`;")  
FROM 
    information_schema.ROUTINES 
WHERE  
    ROUTINE_TYPE = "FUNCTION" 
AND 
    ROUTINE_SCHEMA = "db1";

7, delete all stored procedures

db1: database name

SELECT 
    CONCAT("DROP PROCEDURE `",ROUTINE_NAME,"`;")  
FROM 
    information_schema.ROUTINES 
WHERE  
    ROUTINE_TYPE = "PROCEDURE" 
AND 
    ROUTINE_SCHEMA = "db1";