Question

我有一个包含列

的表格

    drop TABLE "public"."opportunities";
CREATE TABLE "public"."opportunities" ( 
     "itemcode"     VARCHAR COLLATE "default", 
     "creationtime" TIMESTAMPTZ(6) NOT NULL, 
     "finishtime"   TIMESTAMPTZ(6), 
     "ordertag"     INT8, 
     "trackingblob" VARCHAR
); 
insert into opportunities VALUES ('1', now(), null, NULL, 'blob1');
insert into opportunities VALUES ('1', now(), null, 2, 'blob2');
insert into opportunities VALUES ('1', now(), null, null, 'blob3');
insert into opportunities VALUES ('2', now(), null, NULL, 'blob1a');
insert into opportunities VALUES ('2', now(), null, 2, 'blob2a');
insert into opportunities VALUES ('2', now(), null, null, 'blob3a');

预期结果将是具有blob1和blob1a的行。

我想得到每个orderTag，前一个条目的跟踪blob与OrderTag为null - 时间戳之后可能还有行也应该被忽略。这可能在一个SQL中，还是我需要用两个步骤编写程序？

Answer 1

select * from opportunities op1
where (select ordertag from opportunities op2
       where op2.creationtime =
           (select min(creationtime) from opportunities op3
            where op3.creationtime > op1.creationtime)) is not null

即。返回下一行的一行（creationtime-wise）有一个非空的ordertag。

获取第一行为null

1 个答案: