任何人都可以帮助以下链接修改光标

Posted 2023-03-28

【中文标题】任何人都可以帮助以下链接修改光标

【英文标题】：Can anybody help be for below link modified cursor

【发布时间】：2016-10-20 06:26:28

【问题描述】：

我修改了我的函数来执行一些 json 对象

cursor loop in PostgreSQL

我有查询返回以下结果

SELECT asn."Id",asn."UserId",asn."ActivityId",pd."DataSourceId",ad."Dump"
   FROM "Development"."ActivitySession" as asn inner join "Development"."PersonDataSource" as pd on pd."UserId" = asn."UserId" inner join "Development"."ActivitySessionDump" as ad 
   on asn."Id"=ad."ActivitySessionId" where asn."CreatedAt" between now() - interval '5 days' and now() and asn."ActivityId"=1  and pd."DataSourceId"=1



Id                        UserId    ActId   DId  Dump
42594890910270849   42031336811660529   1   1   "activities-steps":["dateTime":"2016-10-17","value":"4023"]
42595097786975653   42031336811660529   1   1   "activities-steps":["dateTime":"2016-10-17","value":"4023"]
42597154682570183   42031336811660529   1   1   "activities-steps":["dateTime":"2016-10-17","value":"5388"]
42602824351352325   42031336811660529   1   1   "activities-steps":["dateTime":"2016-10-18","value":"0"]
42605659177354793   42031336811660529   1   1   "activities-steps":["dateTime":"2016-10-18","value":"0"]
42611328851117671   42031336811660529   1   1   "activities-steps":["dateTime":"2016-10-18","value":"0"]

我在下面写了一个函数

CREATE OR REPLACE FUNCTION ThirdPartyDataParse()
RETURNS text AS $$
DECLARE 
sessionid NO SCROLL CURSOR FOR SELECT asn."Id",asn."UserId",asn."ActivityId",pd."DataSourceId",ad."Dump"
   FROM "Development"."ActivitySession" as asn inner join "Development"."PersonDataSource" as pd on pd."UserId" = asn."UserId" inner join "Development"."ActivitySessionDump" as ad 
   on asn."Id"=ad."ActivitySessionId" where asn."CreatedAt" between now() - interval '5 days' and now() and asn."ActivityId"=1  and pd."DataSourceId"=1 for read only;
titles TEXT DEFAULT '';
rec record;
jsonrec record;
 BEGIN
 OPEN sessionid;
loop

FETCH sessionid INTO rec;
--raise notice '%d',rec."UserId";
   if not found then
        exit ;
   end if;
--titles := titles || ',' || rec."Dump";
 EXECUTE 'SELECT rec."Dump"::json#>''activities-steps,0''->>''value''' INTO jsonrec;
titles := titles || ',' || jsonrec."steps";
end loop;
return titles;
END;
$$ LANGUAGE plpgsql;

但我无法执行

EXECUTE 'SELECT rec."dump"::json#>''activities-steps,0''->>''value''' INTO jsonrec;

rec."dump" 这里等于 "activities-steps":["dateTime":"2016-10-17","value":"4023"]，所以我的查询就像

SELECT '"activities-steps":["dateTime":"2016-10-17","value":"4023"]'::json#>'activities-steps,0'->>'value' as steps;

但我无法执行这个内部函数错误是：

Error in query: ERROR: missing FROM-clause entry for table "rec"
LINE 1: SELECT rec."Dump"::json#>'activities-steps,0'->>'value'
QUERY: SELECT rec."Dump"::json#>'activities-steps,0'->>'value'
CONTEXT: PL/pgSQL function thirdpartydataparse() line 19 at EXECUTE statement

【参考方案1】：

您不能在命令字符串中包含对 PL/pgSQL 变量的引用。 SQL 解析器不知道这些变量，因此它假定您正在请求表 rec 的属性 "Dump"，然后如果该表没有 FROM 子句，则会抱怨。

你需要像这样使用EXECUTE ... USING：

EXECUTE 'SELECT $1::json#>''activities-steps,0''->>''value'''
   INTO jsonrec USING rec."Dump";

【讨论】：

我想使用 EXECUTE 'INSERT INTO "Development"."ActivitySessionParameter" ("ActivitySessionId", "GameParameterId", "Value") VALUES (rec."Id",rec." ActivityId", jsonrec."steps")';但错误是查询中的错误：错误：缺少表“rec”的 FROM 子句条目