SELECTfirst_name,last_name,salaryFROMemployeesorderbysalarydescOFFSET10ROWSfetchfirst10rowsonly; OFFSET表示先忽略掉多少行数据,然后再返回后面的结果。ROWS也可以写成ROW。对于应用程序而言,只需要传入不同的OFFSET偏移量和FETCH数量,就可以在结果中任意导航。使用LIMIT加上OFFSET同样可以实现分页效果: SELECTfirst_name...
postgres=# select userid,userid::regrole from pg_stat_statements group by userid; -[ RECORD 1 ]--- userid | 10 userid | postgres ... 查询Top SQL: -- 按总执行时间查询Top SQL select userid::regrole as user_name,* from pg_stat_statements order by total_exec_time desc limit 20;...
pg_stat_statements.track控制统计数据规则,top用于追踪top-level statement(直接由客户端方发送的),all还会追踪嵌套的statements(例如在函数中调用的statements) pg_stat_statements.track_utility(boolen) pg_stat_statements.track_utility控制是否跟踪公共程序命令(utility commands),公共程序命令是SELECT/INSERT/UPDATE/D...
plpgsql | 1.0 | pg_catalog | PL/pgSQL procedural language (3 rows) 1. 2. 3. 4. 5. 6. 7. 8. 查询pg_stat_statements SELECT query, calls, total_time, rows, 100.0 * shared_blks_hit /nullif(shared_blks_hit + shared_blks_read, 0) AS hit_percent FROM pg_stat_statements ORDER BY...
(4rows) 使用窗口查询的结果举例 postgres=# select * from (select row_number() over(partitionbyc1 orderbyc2)asrn,* from tbl) twheret.rn<=10; rn |c1|c2|c3---+---+---+---1|0|1657|2|0|3351|3|0|6347|4|0|12688|5|0|16991|6|0|19584|7|0|24694|8|0|36646|9|0|40882|10|...
--查询语句总调用次数大于10次，平均运行时间倒序的SQL SELECTt.userid,t.dbid,t.query || ';',t.calls,t.total_time,t.rows,t.total_time / t.calls FROMpg_stat_statements t WHERE(t.calls ISNOTNULLOR t.calls <> 0)ANDt.query !~ '^COPY|<insufficient privilege'ANDt.calls > 10 ORDERBY7...
对于数组可以用unnest函数化为多行然后left join,例如select * from pg_index对于系统的索引表中 indkey字段,对于复合主键就需要化为多行然后关联 unnest(anyarray)setof anyelementexpand an array to a set of rowsunnest(ARRAY[1,2]) 1 2 (2 rows) ...
[postgres@shawnpc bin]$./psqlpsql(13devel)Type"help"forhelp.postgres=# selectrow_number()over()asrownum,id from aa;rownum|id---+---1|12|23|34|45|56|67|78|89|910|10(10rows)postgres=# row_number代码: 代码语言:javascript 复制 /* ...
select name,price,avg (price) over (order by name rows 2 preceding) as moving_avg from product; 这里我们使用了 ROWS (“行”)和 PRECEDING (“之前”)两个关键字,将框架指定为“截止到之前 ~ 行”,因此“ ROWS 2 PRECEDING ”就是将框架指定为“截止到之前 2 行”,也就是将作为汇总对象的记录限...
-> Sort (cost=69214.06..71714.06rows=1000000width=16) (actualtime=0.096..0.097rows=10loops=1) Sort Key: v1, v2 SortMethod: top-N heapsort Memory:25kB ->IndexScanusingtest_v1_idxontest (cost=0.42..47604.42rows=1000000width=16) (actualtime=0.017..0.066rows=56loops=1) ...