Modifying table names, deleting tables, obtaining table information, and deleting table records on specified dates for common MySQL statements

Preface

Why does the operation table use commands , Instead of using simple visual tools to operate directly ？

When the amount of data is small , Using visualization tools is obviously more user-friendly , Simple mouse click operation , Get started without learning .
But as the amount of data increases , It is not realistic to use visualization tools , such as ： A big watch with 30million lines , How can we manage it by hand ？
Using the command line , Obviously, it is more convenient and less error prone .

How to modify the table name

give an example ：
ALTER table A RENAME TO B;
Keep watch A Rename table B

How to delete a table

Use here drop Delete , About drop,delete,truncate See the difference between the two ：
https://blog.csdn.net/GBS20200720/article/details/125128287?ops_request_misc=%257B%2522request%255Fid%2522%253A%2522165613788116782248557404%2522%252C%2522scm%2522%253A%252220140713.130102334.pc%255Fblog.%2522%257D&request_id=165613788116782248557404&biz_id=0&utm_medium=distribute.pc_search_result.none-task-blog-2_blogfirst_rank_ecpm_v1~rank_v31_ecpm-4-125128287-null-null.nonecase&utm_term=drop&spm=1018.2226.3001.4450

drop：
DROP TABLE A;
A Is the name of the watch

How to get the basic information of a table

select * from information_schema.tables where table_name=‘A’;
A Is the name of the watch

Here are some important parameters

TABLE_ROWS（ The number of rows in the table ）：39137335

AVG_ROW_LENGTH（ Average length per row ）：126

DATA_LENGTH（ Data length ）：4951375872

How to delete a table record on a specified date

Get the data three months ago sql：

SELECT *
FROM tp_order_cancel_log
WHERE add_time < curdate() - INTERVAL 3 MONTH
ORDER BY add_time DESC;

add_time It is the field of record creation time defined in my table （ More commonly used is create_time）

Delete data three months ago sql：
DELETE *
FROM tp_order_cancel_log
WHERE add_time < curdate() - INTERVAL 3 MONTH;