PostgreSQL sql 总结

//更新过期的

update

capture set flag=1 where (extract (epoch from now())::bigint-extract (epoch from capture_time )::bigint)>time_val

--系统表

pg_stat_activity 数据库活动进程视图

Pg_database 系统数据库字典

Pg_stat_database系统统计数据库字典视图

Pg_stat_sys_tables 系统字典表

Pg_stat_sys_indexes系统字典表索引

Pg_stat_user_tables用户表

Pg_stat_user_indexes 用户表索引

pg_stat_all_tables 数据库所有的表（包括系统表和用户表）

pg_stat_all_indexs数据库所有的表的索引（包括系统表和用户表的索引）

select datname,procpid,query_start,current_query,waiting,client_addr ,usename from pg_stat_activity ;

--查询更新语句

select datname,procpid,query_start,current_query,waiting,client_addr ,usename from pg_stat_activity where and current_query like '%update%';

ps aux|grep postgres|grep 14190

--取消查询语句

select pg_cancel_backend(14190);

--kill 各种sql

pg_terminate_backend(pid int),

psql -h .. -p .. -d db_name -U username -c "copy public.test_1 to stdout" > test_1.out

除0

NULLIF 等价＝case when

select count(nullif(answer_time_of_date,'0')) as succ_calls from client_cdr

select count(case when answer_time_of_date ='0' then null else answer_time_of_date end) as succ_calls from client_cdr

select count(case when release_cause_from_protocol_stack ~* '^486*' then release_cause_from_protocol_stack else null end) as busy_calls from client_cdr

exchange=# select 3/NULLIF(0,0);

SELECT COALESCE(SUM(amount), 0) / NULLIF(SUM(current_balance), 0) as average_price FROM client_payment

--防止除0

select 3/0

select 3/NULLIF(0,0)

SELECT COALESCE(SUM(cost), 0) / NULLIF(SUM(amount), 0) as average_price FROM sales

SELECT *, first_name||' '||last_name AS full_name FROM test_table;

--取出几个列中最大的值

select LEAST(current_balance,amount) from client_payment where client_payment_id=1

--取出几个列中最大的值

select greatest(current_balance,amount) from client_payment where client_payment_id=1

--取出几个列中不为空的值

select COALESCE(current_balance,amount) from client_payment where client_payment_id=1

--取出几个列中空的值

select NULLIF(current_balance,amount) from client_payment where client_payment_id=1

在PostgreSQL中实现行号

2010-05-28 09:30

建立一个序列，每次查询果将其当前值设置为0，然后用nextval()函数取值就可以

create sequence test_row;

select setval('test_row',1);

select nextval('test_row')-1 as rowno ,table.* from table;

:%s/,\n/\r/g --去掉最后一个,

:%s/^1//g--去掉第一个1

--PostgreSQL中如何删除重复记录

--ostgreSQL中删除重复记录其实很简单，不论有多少行重复，只要在要删除重复记录的表中table加一列rownum字段(id为table表中的主键)，类型设置为serial类型即可，然后执行sql

--删除原理添加一个自增列, 按照重复的字段分组，取出rownum最大的一列,这一列就是去掉重复后的列

insert into version values(3,'22','333')

--添加自增字段

ALTER TABLE "version" ADD COLUMN rownum serial;

--去掉重复后的结果

select * from version where rownum in ( select max(rownum) from version group by table_name )

--删除重复

delete from version where rownum not in ( select max(rownum) from version group by table_name )

--知道有什么用户在访问，访问什么库以及访问的进程

select datid,datname,procpid,usename, xact_start from pg_stat_activity;

--kill 查询 ill Select 查询，而updae,delete DML不生效

select pg_cancel_backend(线程id);

--查看有哪些SQL正在执行

select datname,procpid,query_start,current_query,waiting,client_addr from pg_stat_activity where waiting='t';

--最近15分钟的acd ,asr ,pdd,ca

--15 min

select

sum(call_count_asr::integer*asr::real)/sum(call_count_asr::integer) as asr,

(sum(acd::real)/sum(call_count::integer))/60 as acd,

(sum(pdd::real) / sum(call_count::integer)) as pdd, sum(ca::integer) as ca

into r from host_info

where ip=host_ip and time::bigint between extract(epoch from now())::bigint-(60*15) and extract(epoch from now())::bigint;

select extract (epoch from now())::bigint //当前时间对应的时间戳

select now()//现在时间

update host_info set time=(select extract(epoch from '2010-12-21 01:52:10.849097+00'::timestamp with time zone )::bigint)

--累加sql

select invoice_id, client_id ,

(select sum(total_amount) as past_due from invoice as inner_invoice where client_id = invoice.client_id and inner_invoice.invoice_end <= invoice.invoice_end) as total from invoice;

update host_info set time=(select extract(epoch from '2010-12-20 11:22:10.849097+00'::timestamp with time zone )::bigint)

----------备份cdr

class4_pr=# copy (select * from client_cdr limit 1) to '/tmp/exports/cdr.csv' csv HEADER;

--导入cdr

class4_pr=# copy client_cdr from '/tmp/exports/cdr.csv' csv HEADER ;

---------------------------------------------------------------重建触发器

psql carry_sst < /home/test/record.sql

SELECT *

FROM prefixes

WHERE prefix @> '0123456789'

ORDER BY length(prefix) DESC

LIMIT 1;

EXPLAIN ANALYZE

touch /var/lock/subsys/local

svnserve -d -r /shanmin/svn

----------------------------------------------------------------------

COPY----------- 用法-

-----------------------------------------------------------------------

COPY error_message_info FROM '/tmp/message.csv' CSV HEADER ;//导入

COPY (select * from error_message_info limit 2) TO '/tmp/message1.csv' CSV HEADER ;//导出

---case when 用法

case when call_duration='' then '0' ELSE call_duration end ,

select call_count, case when call_count='0' then '1' ELSE call_count end

from host_info where call_count='0'

---v---------------v------------------各种时间转换---v------------------v---------------

SELECT to_timestamp(start_time_of_date::bigint) as time from cdr

--时间处理

select extract(epoch from (logout_time -login_time )) from acd_login_log

SELECT EXTRACT(EPOCH FROM INTERVAL '5 days 3 hours');

实现按月按年，按日统计

把数据库里的数据按每一天统计当天的点击量，当然是用 group by，可惜问题是时间字段存储为bigint型，看来还得先转成timestamp型的，于是翻了手册，写了如下SQL搞定！

select to_char(to_timestamp(accesstime), ‘YYYY-MM-DD’) as d, count(validclick) as c from dbtm_ad_list group by d order by c desc

其中to_timestamp()函数将int型数据转换为timestamp类型的值，格式为”YYYY-MM-DD”，再将其值用to_char()函数转换为文本类型，便可以用group by分组了。

select ( current_timestamp(0) - interval '24 hour')

--将微秒改为时间戳

SELECT to_timestamp(substring(answer_time_of_date from 1 for 10) ::bigint)from client_cdr

//更新当前时间

update host_info set time=(select EXTRACT(EPOCH from current_timestamp(0)))::text

select * from current_timestamp(0) =="2010-11-10 10:40:46+08"

select EXTRACT(EPOCH from current_timestamp(0)) (1289356894)

--将 1289356894转换为 2010-11-10 10:40:46+08

SELECT to_timestamp(time::bigint) from host_info

-- Column: create_time 给字段设置默认值为当前时间

-- ALTER TABLE account_balance DROP COLUMN create_time;

ALTER TABLE account_balance ADD COLUMN create_time timestamp with time zone;

ALTER TABLE account_balance ALTER COLUMN create_time SET STORAGE PLAIN;

ALTER TABLE account_balance ALTER COLUMN create_time SET NOT NULL;

ALTER TABLE account_balance ALTER COLUMN create_time SET DEFAULT ('now'::text)::timestamp(0) with time zone;

COMMENT ON COLUMN account_balance.create_time IS '改动时间';

---v---------------v------------------各种时间转换---v------------------v---------------

--导出数据库表结构

[root@class4 tmp]# /usr/local/pgsql/bin/pg_dump -s class4v3_test > tmp.sql

--导入数据库表结构

[root@class4 tmp]# psql class4v3 < tmp.sql

--sql

CASE account_payment.payment_method

WHEN 0 THEN '系统充值卡 '::text

WHEN 1 THEN '快钱'::text

WHEN 2 THEN '系统管理员(手工充值)'::text

WHEN 3 THEN '易宝'::text

ELSE 'other'::text

END AS payment_method1,

--pg_dump 导出sql数据

利用select into语句创建一个临时表，然后使用pg_dump导出临时表。

select * into test_tbl from some_tbl where some_field > some_value;

pg_dump -d db_name -t test_tbl > /tmp/test.sql

/tmp/test.sql里面包含的，就是要求的特定记录了。

--模糊查询

$condition="'%".$key."%'";

select resource.alias,resource.resource_id , resource.name ,cps_limit,capacity,ingress,egress,active, a.ip_cnt , client_id

from resource

left join (select count(*)as ip_cnt,resource_id from resource_ip group by resource_id) a on a.resource_id=resource.resource_id

where resource.name like $condition

or resource.alias like $condition

or ( select count(*)>0 from resource_ip where resource_ip.resource_id =resource.resource_id and resource_ip.ip::varchar like $condition )

order by resource.resource_id limit '$pageSize' offset '$offset'

-- --前缀匹配的用法只取

select into id_rate rate_id from rate

where rate_table_id = id_rate_table and code @> NEW.origination_destination_number::prefix_range and current_timestamp between effective_date and end_date order by code desc limit 1;

$code_where=" and origination_destination_number::prefix_range <@ '$code'";

select * from cdr where origination_destination_number::prefix_range <@ '$code'";

select trunk.trunk_ip||':'||trunk.port address, trunk.trunk_id from

prefix,trunk where trunk.trunk_id = prefix.trunk_id and prefix_code @>'%

s' order by length (prefix_code::text) desc limit 1

--in的替代解决办法

SELECT　*

FROM　tab

WHERE　col1　IN　(SELECT　col2　FROM　TAB2)

select * from client where client_id::text in (select client_id from class4_view_client_cost )

改为：　

select * from client where exists(select client_id from class4_view_client_cost

where class4_view_client_cost.client_id::integer=client.client_id)

SELECT　*

FROM　tab

WHERE　EXISTS　(SELECT　col2　FROM　TAB2　WHERE　col1　=　col2)

--建立索引

-- Index: code_index_code

-- DROP INDEX code_index_code;

CREATE INDEX code_index_code

ON code

USING btree

(code);

--索引测试

--索引前执行 4452 ms

select * from class4_view_client_cost

--索引后执行 14ms

--prefix 特有的索引

-- Index: idx_code_prefix

-- DROP INDEX idx_code_prefix;

CREATE INDEX idx_code_prefix

ON code

USING gist

(code gist_prefix_range_ops);

--导出sql

$copy_sql = "COPY ($download_sql) TO '$copy_file' DELIMITER '$DELIMITER' CSV $HEADER "; //daochu

--导入sql

cmd:='COPY ' || table_name || '(ani,dnis,action_ani,action_dnis,ani_method,dnis_method) FROM '''||filecsv ||''' CSV HEADER';

--删除重复行

id name score

1 aaa 30

2 aaa 30

3 aaa 36

4 bbb 30

5 bbb 30

6 aaa 30

7 bbb 30

8 ccc 24

9 ccc 51

保留同NAME中ID最小.

delete tb from tb t where id not in (select min(id) from tb where name = t.name)

保留同NAME中ID最大.

delete tb from tb t where id not in (select max(id) from tb where name = t.name)

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