小编tom*_*mss的帖子

你能给出一个使用tm(我不知道如何初始化struct)的例子,其中当前日期是用这种格式写的y/m/d吗？

我试过这个问题:在不到2家医院工作的医生是什么？但结果并不是我的预期.

我有这些表:

CREATE TABLE Hospital (
    hid INT PRIMARY KEY,
    name VARCHAR(127) UNIQUE,
    country VARCHAR(127),
    area INT
);
CREATE TABLE Doctor (
    ic INT PRIMARY KEY,
    name VARCHAR(127),
    date_of_birth INT,
);
CREATE TABLE Work (
    hid INT,
    ic INT,
    since INT,
    FOREIGN KEY (hid) REFERENCES Hospital (hid),
    FOREIGN KEY (ic) REFERENCES Doctor (ic),
    PRIMARY KEY (hid,ic)
);

我试过这个:

SELECT DISTINCT D.ic 
    FROM Doctor D, Work W 
    JOIN Hospital H ON (H.hid = W.hid)
    WHERE D.bi = W.bi
    GROUP BY (D.ic) …