Question

首先我创建了两个表：

CREATE TABLE min_data(
id integer primary key,
ic char(5) not null,
dt datetime not null,
cou float,
max float not null,
avg float not null,
min float not null);

CREATE TABLE min_data(
id integer primary key,
ic char(5) not null,
dt datetime not null,
cou float,
max float not null,
avg float not null,
min float not null);
CREATE UNIQUE INDEX in_ic_dt on hour_data(ic, dt);

然后我按如下方式创建了一个触发器。

create trigger ins after insert on min_data
begin
    replace into hour_data(ic, dt, cou, max, avg, min) 
    select ic, strftime('%Y-%m-%d %H:00:00', dt), AVG(cou) * 6, MAX(max), AVG(avg), MIN(min) from min_data where strftime('%Y-%m-%d %H:00:00', new.dt) <= dt and dt < strftime('%Y-%m-%d %H:00:00', new.dt, '+1 hour') and ic = new.ic;
end;

这是问题所在。在我将一些记录插入min_data之后，触发器会将一些记录插入到hour_data中，但是hour_data中记录的id不以1开头并且是离散的。我该如何解决这个问题？

Answer 1

REPLACE不会更新现有记录;它只删除任何旧记录，然后插入一个新记录。

您必须手动更新或插入：

CREATE TRIGGER ...
BEGIN
    -- update the old record, if it already exists:
    UPDATE hour_data
    SET cou = (SELECT AVG(cou) * 6 ...),
        max = (SELECT MAX(max) ...),
        ...
    WHERE ic = NEW.ic
      AND dt = strftime('%Y-%m-%d %H:00:00', NEW.dt);

    -- insert the new record,
    INSERT INTO hour_data(...)
    SELECT ...
    WHERE ...
      -- if it does not yet exist:
      AND NOT EXISTS (SELECT 1
                      FROM hour_data
                      WHERE ic = NEW.ic
                        AND dt = strftime('%Y-%m-%d %H:00:00', NEW.dt));
END;

sqlite3上触发器中的replace语句

1 个答案: