POSTGRESQL GROUP BY 技术教程文章
PostgreSQL对GROUP BY子句使用常量的特殊限制【代码】
一、问题描述最近，一个统计程序从Oracle移植到PostgreSQL（版本9.4）时，接连报告错误：错误信息1： postgresql group by position 0 is not in select list.错误信息2： non-integer constant in GROUP BY.产生错误的sql类似于：insertinto sum_tab (IntField1, IntField2, StrField1, StrField2, cnt) select IntField, 0, StrField, ‘null‘, count(*) from detail_tab where ... groupby IntField, 0, StrField, ‘null‘;其...
postgresql group by 报错【代码】
SELECT cname, wmname, MAX(avg) FROM makerar GROUP BY cname; 错误： ERROR: column "makerar.wmname" must appear in the GROUP BY clause or be used in an aggregate function LINE 1: SELECT cname, wmname, MAX(avg) FROM makerar GROUP BY cname; 首先这个错误的原因是因为： Before SQL3 (1999), the selected fields must appear in the GROUP BY clause[*].Interestingly enough...
PostgreSQL group by 后取最新的一条【代码】【图】
PostgreSQL group by 后取最新的一条 参考：https://www.cnblogs.com/funnyzpc/p/9311281.html，https://www.cnblogs.com/aeolian/p/9359898.html 需求针对 registration_id 和 district 分组(登记编号、区) 并且根据时间倒序取最后一条数据请注意，id=1,2的两条数据经过双重分组查询后的结果应该是两条CREATE TABLE "public"."application" ("id" int8 NOT NULL,"district" varchar(255) COLLATE "pg_catalog"."default","registr...
PostgreSQL GROUP BY与MySQL不同？【代码】
我一直在将一些MySQL查询迁移到PostgreSQL以使用Heroku.我的大多数查询工作正常,但当我使用group by时,我仍然遇到类似的重复错误：ERROR: column “XYZ” must appear in the GROUP BY clause or be used inan aggregate function有人能告诉我我做错了什么吗？ MySQL 100％工作：SELECT `availables`.* FROM `availables` INNER JOIN `rooms` ON `rooms`.id = `availables`.room_id WHERE (rooms.hotel_id = 5056 AND availables....
postgresql group by 报错【代码】
举个例子： ????table?name:makerar cname??|?wmname?|??????????avg??????????? --------+-------------+------------------------ ? canada?|?zoro???|?????2.0000000000000000 spain??|?luffy??|?1.00000000000000000000 ? spain??|?usopp??|?????5.0000000000000000 ? 执行语句： ?1 SELECT cname, wmname, MAX(avg) FROM makerar GROUP BY cname;? ? 错误： ???? ERROR:??column?"makerar.wmname"?must?appear?in?the?GROU...