建立表：
create table tablename
(field1 integer not null peimary key, //int，不為空，主鍵
field2 character varying(10) not null, //char，10個位元組，不為空
field3 serial not null, //int,自增，不為空
field4 text, //char，文字
field5 numeric, //int，數字
field6 timestamp without time zone, //不帶時區的時間
field7 numeric default 0) //int，數字，預設0
insert into tablename(field1,field2,field3) values(1,'%2',3,'%4',5,'2060-06-06','7')//不為空
select * from "tablename" where "fieldname" is not null
//為空
select * from "tablename" where "fieldname" is null
select sum("field") from "tablename"select count("field") from "tablename"select "filed" from "tablename" where "field" between '' and ''select "fieldname" from "tablename" where "field" ~* '^%1$'//全匹配%1
select "fieldname" from "tablename" where "field" ~* '%1'//不匹配%1
select "fieldname" from "tablename" where "field" ~* '%1$'//後匹配%1
select "fieldname" from "tablename" where "field" ~* '^%1'//前匹配%1
//多條件查詢
select "fieldname" from "tablename" where "field1" ~* '%1' and "field2" ~* '%2'
select "fieldname" from "tablename" where "field" ~* '%1' or "field" ~* '%2'
//跨表查詢
select "fieldname1" from "tablename1" where "field1" in (select "fieldname2" from "tablename2" where "field2" ~* '%1')
//通過多條件查詢跨表統計某欄位個數
select count(*) from "tablename1" where "fieldname1" in (select "fieldname2" from "tablename2" where ("field1" ~* '%1' or "field1" ~* '%2') and ("filed2" between '%3' and '%4') ) or "fieldname3" in (select "fieldname4" from "tablename3" where ("filed3" ~* '%5'))
select distinct "field" from "tablename" where "field" is not null最終查詢的字段必須在group by裡出現
select concat("fieldname1","fieldname2"),"fieldname1" from "tablename" group by concat("fieldname1","fieldname2")//查詢拼接fieldname1，filedname2欄位不重複資料
select "fieldname1" from (select concat("fieldname2","fieldname3"),"fieldname1" from "tablename" group by concat("fieldname2","fieldname3"),"fieldname1") name
//查詢欄位fieldname1，條件是滿足拼接fieldname2，fieldname3後不重複的資料
//name是from需求的別名
例項:查詢圓柱體表的直徑與高資料，每個圓柱體的唯一識別符號是頭尾結點，條件是圓柱體不重複
select "d_s","length" from (select concat("s_point","e_point"),"d_s","length" from table
group by concat("s_point","e_point"),"d_s","length") sum
postgres sql 備份還原
postgresql自帶乙個客戶端pgadmin，裡面有個備份，恢復選項，也能對資料庫進行備份 恢復 還原 但最近發現資料庫慢慢龐大的時候，經常出錯，備份的檔案過程中出錯的機率那是相當大，手動調節灰常有限。所以一直尋找完美的備份恢復方案。用法 備份資料庫 指令如下 pg dump h 164.82....
Postgres SQL儲存函式引數使用說明
在使用postgres資料庫的過程中，遇到了表分割槽的問題。為了建立表分割槽，首先得建立分割槽表。首先想到的是寫個儲存函式，然後定時的建立分割槽表，然後再建立觸發器去操作分割槽表。但是在建立儲存函式時，怎麼把分割槽表的表名當作引數傳進儲存函式，然後在函式內部動態建立表。可是直接使用字串的表名不起作用...
PostgresSQL常用客戶端命令
連線資料庫,預設的使用者和資料庫是postgres psql u user d dbname 切換資料庫,相當於mysql的use dbname c dbname 列舉資料庫，相當於mysql的show databases l 列舉表，相當於mysql的show tables dt 檢視表結構，相當...