How does mysql count the amount of data in each table in a database?

I'm migrating a database recently and want to compare whether the data volume before and after migration is consistent to avoid missing data.

sql：

SELECT
	table_name,
	table_rows 
FROM
	information_schema.TABLES 
WHERE
	TABLE_SCHEMA = "你的数据库名称" 
ORDER BY
	table_rows DESC;

Just found a test library

If you want to count the total amount of data in the entire database, you can also

SELECT
	sum(table_rows)
FROM
	information_schema.TABLES 
WHERE
	TABLE_SCHEMA = "你的数据库名称" 
ORDER BY
	table_rows DESC;

In fact, these data are all in the metadata database that comes with mysql.

Each mysql has its own information_schema library, which records all information about the mysql service, including which tables, indexes, etc.

The information we just needed is in the TABLES table

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Laughing to death, you don’t need to read the above. After working on it for a long time, the data is not accurate. After reading the MySQL document, the schema library of innodb is just an estimate. 嘤嘤嘤~