sql - 使用 ORDER BY 更新

Question

需要将 UPDATE 与 ORDER BY“绑定(bind)”。我正在尝试使用游标，但出现错误:

cursor "cursupd" doesn't specify a line,
SQL state: 24000

代码:

BEGIN;
    DECLARE cursUpd CURSOR FOR SELECT * FROM "table" WHERE "field" = 5760 AND "sequence" >= 0 AND "sequence" < 9 ORDER BY "sequence" DESC;
    UPDATE "table" SET "sequence" = "sequence" + 2 WHERE CURRENT OF cursUpd;
    CLOSE cursUpd;
COMMIT;

如何正确操作？

更新 1

没有光标，当我这样做时:

UPDATE "CableLinePoint" AS "t"
SET "sequence" = t."sequence" + 2
from (
    select max("sequence") "sequence", "id"
    from "CableLinePoint"
    where
        "CableLine" = 5760
    group by "id"
    ORDER BY "sequence" DESC
) "s"
where "t"."id" = "s"."id" and "t"."sequence" = "s"."sequence"

我得到了独特的错误。所以，需要从最后而不是从头开始更新。

更新 2

表:

id|CableLine|sequence
10|    2    |    1
11|    2    |    2
12|    2    |    3
13|    2    |    4
14|    2    |    5

需要更新(增加)字段“sequence”。 "sequence"有 "index"类型，所以不能这样做:

UPDATE "table" SET "sequence" = "sequence" + 1 WHERE "CableLine" = 2

当 id = 10 行中的“sequence”增加 1 时，我收到一个错误，另一行 “sequence” = 2 已经存在。

Answer 1

UPDATE 和 ORDER BY:

UPDATE thetable 
  SET columntoupdate=yourvalue 
 FROM (SELECT rowid, 'thevalue' AS yourvalue 
         FROM thetable 
        ORDER BY rowid
      ) AS t1 
WHERE thetable.rowid=t1.rowid;

UPDATE 顺序仍然是随机的(我猜)，但是提供给 UPDATE 命令的值与 thetable.rowid=t1.rowid 条件。所以我正在做的是，首先选择内存中的“更新”表，它在上面的代码中被命名为 t1，然后使我的物理表看起来与 t1 相同.更新顺序不再重要。

至于真正有序的 UPDATE，我不认为它对任何人都有用。