CREATE OR REPLACE FUNCTION f_trig_() RETURNS trigger AS $$ DECLARE BEGIN IF (TG_OP = 'DELETE') THEN OLD.tech_end = CURRENT_TIMESTAMP; INSERT INTO hist_ values (OLD.*); return OLD; ELSIF (TG_OP = 'UPDATE') THEN OLD.tech_end = CURRENT_TIMESTAMP; NEW.tech...
AI代码解释 drop table u1tbl;create tableu1tbl(i int);insert into u1tblvalues(1);insert into u1tblvalues(2);insert into u1tblvalues(3);dropfunctionf1();CREATEORREPLACEFUNCTIONf1()RETURNSintAS$$DECLAREid int;i1 int:=1;i2 int:=2;BEGINEXECUTE'SELECT sum(i) FROM u1tbl WHERE i >= $1 ...
根据社区邮件的讨论,PostgreSQL 17 开始对被smgropen后的存储层对象有了明确的生命周期定义,保证事务结束前存储层对象不会失效。 /** smgropen() -- Return an SMgrRelation object, creating it if need be.** In versions of PostgreSQL prior to 17, this function returned an object* with no defined lif...
问PostgreSQL中的递归/迭代约简EN目前，我正在与递归CTE进行斗争，因为我需要在每个循环中引用CTE的结果输...
(SubqueryScanState *) node); break; case T_FunctionScanState: result = ExecFunctionScan((FunctionScanState *) node); break; case T_ValuesScanState: result = ExecValuesScan((ValuesScanState *) node); break; case T_CteScanState: result = ExecCteScan((CteScanState *) node); break; case...
Group By – divide rows of a result set into groups and optionally apply an aggregate function to each group. Having – apply conditions to groups, which allow you to filter groups. Section 5. Set Operations Union – combine result sets of multiple queries into a single result set. ...
If you need to replace multiple values, you can use the CASE function. select name, platform, case when platform = 'Mac' then null when platform = 'Windows' then null when platform = 'Linux' then null else platform end as platform_mod from users;...
2.1 Declaring Function Parameters Parameters passed to functions are named with the identifiers $1, $2 give a name to the parameter in the CREATE FUNCTION command, for example: CREATEFUNCTIONsales_tax(subtotalreal)RETURNSrealAS$$BEGINRETURNsubtotal*0.06;END; ...
Simple row_filter would look something like row_filter := 'id > 0' which would ensure that only rows where values of id column is bigger than zero will be replicated. It's allowed to use volatile function inside row_filter but caution must be exercised with regard to writes as any expr...
CREATEORREPLACEFUNCTIONinsert_into_t2()RETURNStriggerAS$$BEGININSERTINTOt2VALUES(NEW.a,NEW.b);RETURNNEW;END;$$languageplpgsql; Event Trigger 创建Event Trigger的语法如下,相比 Trigger 的语法要简单很多 CREATEEVENTTRIGGERnameONevent[WHENfilter_variableIN(filter_value[,...])[AND...]]EXECUTE{FUNCTION|PR...