查询所有库名

show databases;

SELECT distinct(TABLE_SCHEMA) dbname FROM information_schema.TABLES

查询所有表名

SELECT table_name,`engine` from information_schema.tables where table_schema='dbname' and table_type='base table'

查询表是否存在

SHOW TABLES LIKE '%tb_bp_d_case%';

select TABLE_NAME from INFORMATION_SCHEMA.TABLES whereTABLE_SCHEMA='dbname' and TABLE_NAME='tablename' ;

查询表的所有字段

select COLUMN_NAME,DATA_TYPE from information_schema.columns where table_name='tp_papers' and table_schema='gb_activity_2020' ORDER BY ORDINAL_POSITION