postgre 经常使用语法，如 group_concat用法

1.查询postgre的表全部字段列

select table_name, column_name from information_schema.columns
where table_schema='public' and table_name='t_user';

2.将上面的列，group_concat拼接

select string_agg(column_name,',') 
from information_schema.columns
where table_schema='public' and table_name='t_user';

 拼表的自字段查询

select 'select '
||(
select string_agg(column_name,',') from information_schema.columns
where table_schema='public' and table_name='t_user'
)
||' from t_user';

----------------
select id,name,cnname,password from t_user