postgreSQL 应用case when的例子 select name, md5(indvl_id_nbr) as indvl_id_nbr, case when char_length(indvl_id_nbr)=18 or char_length(indvl_id_nbr)=15 then substring(indvl_id_nbr from 1 for 6) end as id_prefix, case when char_length(indvl_id_nbr)=18 then substring(indvl_id...
PostgreSQL 9.6是一种开源的关系型数据库管理系统,它支持广泛的数据类型和功能,适用于各种规模的应用程序。在PostgreSQL 9.6中,可以使用基于列总和的case-when子句来实现条件逻辑。 基于列总和的case-when子句是一种在查询中根据列的值进行条件判断和计算的方法。它的语法如下: 代码语言:txt 复制 SELECT column1, ...
在 OP 中,案例将解析为 NULL,这将导致 WHERE 子句有效地选择 WHERE … AND NULL,这将始终失败。 SELECT * FROM table WHERE t1.id_status_notatka_1 = ANY (selected_type) AND t1.id_status_notatka_2 = ANY (selected_place) AND CASE WHEN t2.id_bank = 12 THEN t1.id_status_notatka_4 = ...
postgreSQL 应用case when的例子 select name, md5(indvl_id_nbr) as indvl_id_nbr, case when char_length(indvl_id_nbr)=18 or char_length(indvl_id_nbr)=15 then substring(indvl_id_nbr from 1 for 6) end as id_prefix, case when char_length(indvl_id_nbr)=18 then substring(indvl_id...
PostgreSQL中关于CASE、WHEN、THEN、END AS的初级问题 postgresql pgadmin-4 我正在遵循一个视频教程,该教程处理CASE、WHEN和END AS</kbd]查询。pgAdmin可以通过SELECT找到它,但当使用CASE时,它就不存在了! 选择film_id,标题,描述,release_year,长度,等级, CASE 当language_id“1”时,则为“英语” 当language_id...
以下是一个示例函数,演示如何在CASE内循环: 代码语言:sql 复制 CREATEORREPLACEFUNCTIONloop_with_case()RETURNSVOIDAS$$DECLAREcounterINT:=1;max_counterINT:=10;BEGINWHILEcounter<=max_counterLOOPCASEWHENcounter<5THEN-- 执行某些操作或返回某些结果RAISE NOTICE'Counter is less than 5: %',counter;WHENcounter...
casewhen语句第一种方式:casewhen表达式1then结果1when表达式2then结果2else结果nend举例1: select sum(casewhenrental_rate=0.99then1else0end)as"aa",sum(casewhenrental_rate=2.99then1else0end)as"bb",sum(casewhenrental_rate=4.99then1else0end)as"cc"from film;结果: aa bb cc341323336【注】:as后接...
thencaseTG_ARGV[2]when'first'thenifOLD.mm_last_xacttime <NEW.mm_last_stattimeor(OLD.mm_last_stattime =NEW.mm_last_stattimeandOLD.mm_nodeid::text=TG_ARGV[3]andNEW.mm_nodeid <>OLD.mm_nodeid)thenreturnnull;endif;when'last'thenifOLD.mm_last_stattime >NEW.mm_last_stattimeor(OLD....
SELECT *, CASE WHEN bool_or(step = 'step3_eu') OVER (PARTITION BY user_id) THEN 'Category 2' ELSE 'Category 1' END as type FROM mytable You can use bool_or() window function. This checks if there is any record with value step3_eu within a group (= partition of user_id). ...
B-tree索引类型,以«btree»访问方法实现的,适合于可排序的数据。换句话说,必须为数据类型定义«greater»、«greater or equal»、«less»、«less or equal»和«equal»操作符。注意,相同的数据有时可能排序不同,这又回到了操作符家族的概念。