数据库实用操作记录 (随时更新）

1. 查询库中所有表名及注释 mytable是要查的库

mysql:

SELECT TABLE_NAME 表名,TABLE_COMMENT 表注释 FROM information_schema.TABLES WHERE table_schema='dbname';

oracle：

SELECT a.TABLE_NAME,b.COMMENTS FROM user_tables a,user_tab_comments b  WHERE a.TABLE_NAME=b.TABLE_NAME ORDER BY TABLE_NAME

2. mongo数据库：或的查询 $or

db.getCollection("Device").find({$or:[{creator_id:'eb7544be-b760-4de6-b76e-ee3223463a3'},{creator_id:'858a50ae-49ba-45ac-ad1c-8d08d0577772'}]})