MySQL Tips: View the mysql database server information command set

– Query MySQL version

select version() from dual;

-View the length of the database string splicing

show variables like 'group_concat_max_len';

-Display the maximum number of MySQL connections

show variables like '%max_connections%';

-Modify the maximum number of connections

-- set GLOBAL max_connections = 200;

-The maximum number of MySQL connections that the server responds to-the ideal setting is: Max_used_connections /

max_connections * 100% ≈ 85% 　　
show status like '%connections%';

-View MySQL threads

show status like '%Threads%';

-To view the storage space occupied by the index in mysql, use the following sql statement

SELECT
table_name,
concat( TRUNCATE ( data_length / 1024 / 1024, 2 ), 'MB' ) AS data_size,
concat( TRUNCATE ( index_length / 1024 / 1024, 2 ), 'MB' ) AS index_size 
FROM
information_schema.TABLES 
WHERE
	table_name = 'ec_order' 
ORDER BY
index_size DESC;

– View the subdivision index of a single table:

select TABLE_SCHEMA,TABLE_NAME,COLUMN_NAME,CARDINALITY from 
information_schema.STATISTICS 	iss
where iss.table_name='ec_order';

-Query table and index occupy space

select * from information_schema.TABLES
where information_schema.TABLES.TABLE_SCHEMA='ftms_union' and 	
information_schema.TABLES.TABLE_NAME='ec_order'

– Query Sql template

select @@global.sql_mode