如果我删除INNER JOIN中的OR语句,只在第一个ID上联接,则查询将在几秒钟内执行,而不是大约半小时。 SELECT DISTINCT ON (ctr.id) ctr.id, ctr.customer_id_1, ctr.date AS contract_date, cst.info, cst.date AS info_date FROM contracts ctr INNER JOIN customers cst ON ( cst.customer_id = ctr....
select distinct on (order_date)cust_id, order_date, order_id from order group by delivery_date, customer_id, delivery_id order by delivery_date asc 本站已为你智能检索到如下内容,以供参考: 1、根据条件获取表中每个月的第一行2、PostgreSQL-如何获取每个月最后一天的所有行3、Postgres SQL查询,获取...
updateas a_horse_with_no_name suggests，union是选择DISTINCT值的方法，因为这里首选UNION ALL-以防万...
MySQL 是不支持 select ... into ，但是可以使用 insert into ... select 当然也可以使用 create ...
每次写入之前,先通过selectnewtape进行选盘操作。 static void selectnewtape(Tuplesortstate *state) { /* * At the beginning of each merge pass, nOutputTapes and nOutputRuns are * both zero. On each call, we create a new output tape to hold the next * run, until maxTapes is reached. Af...
SELECT COALESCE(NULL,'123') != '13'; 10、判断否个字段中是否包含否字符串,类似CHARINDEX(@Param,ColumnName) SELECTdistinctFloorNo,HouseIdFROMpublic.v_SchoolRoomFloorWHEREPOSITION('13000205F100001'INUInstallId) >0ANDHouseId=1ANDStatus=1;SELECTdistinctFloorNo,HouseIdFROMpublic.v_SchoolRoomFloorWHERESTR...
说明 是否必须使用 SELECT 要返回的列或者表达式 是 FROM
Help on CREATE DATABASE command syntax \h CREATE DATABASE Copy // Help on SQL Command Syntax (For e.g. CREATE DATABASE) (psql) Create database CREATE DATABASE mytest; Copy // Creates a new database “mytest” (SQL) By default, the owner of the database is the current login ...
First of all, we're going to talk about the new unique constraint NULLS NOT DISTINCT option, and then we'll talk about the SELECT DISTINCT performance improvements. Share this episode: Click here to share this episode on twitter, or sign up for our newsletter and check out the newsletter ...
SELECT DISTINCT pno FROM p WHERE pname = 'Screw' OR pno IN ( SELECT pno FROM sp WHERE sno = 'S1'); Result: 1 P1, 1 P2 SELECT DISTINCT pno FROM sp WHERE sno = 'S1' OR pno IN ( SELECT pno FROM p WHERE pname = 'Screw'); ...