要点

1. 相当与mysql的show databases;

select datname from pg_database;    

1. 相当于mysql的show tables;

SELECT table_name FROM information_schema.tables WHERE table_schema = 'public';   

public 是默认的schema的名字

1. 相当与mysql的describe table_name;

SELECT column_name FROM information_schema.columns WHERE table_name ='table_name';  

'table_name'是要查询的表的名字