查询oracle数据库所有表数据量
select t.table_name,t.num_rows from user_tables t ORDER BY t.num_rows desc
查询postgresql数据库所有表数据量
select table_schema || '.' || table_name as table_full_name,
pg_size_pretty(pg_total_relation_size('"' || table_schema || '"."' || table_name || '"')) as size
from information_schema.tables
order by
pg_total_relation_size('"' || table_schema || '"."' || table_name || '"') desc
改变配置
pg_ctl reload
分组取前几条:
https://blog.csdn.net/a258831020/article/details/48497929
select t.* from (select serial_group_id, total,year, month, row_number() over(partition by serial_group_id ORDER BY year desc,month desc) as row from ap_serial_group_sales ORDER BY year desc) t where row<=1
相加:
(coalesce(t.local_price,0)+coalesce(t.manu_price,0)+coalesce(t.country_price,0)) btotal
逗号合并:
select array_to_string(ARRAY(SELECT unnest(array_agg(t.id)) ),',') from ( select n.id from ap_group_photo_node n left join ap_group_photo_node_ex ex on ex.group_photo_node_id = n.id left join ap_photo p on n.id = p.group_photo_node_id where n.enabled = 1 and n.deleted = 0 and n.photo_amount > 0 and p.enabled=1 group by n.id order by n.id limit 100 ) t
相同id的合并值:
https://my.oschina.net/Kenyon/blog/86609