我需要找到在VICTORIA AVE上的一家酒馆订购饮品的独特饮酒者。在2020年3月。
以下是我要从中检索数据的表:
CREATE TABLE ORDERS( /* Drinkers visit pubs and consumes drinks */
DRINKER VARCHAR(30) NOT NULL, /* Drinker name */
PUB VARCHAR(30) NOT NULL, /* Pub name */
ODATE DATE NOT NULL, /* Order date */
DRINK VARCHAR(30) NOT NULL, /* Drink name */
DRINK_NO DECIMAL(2) NOT NULL, /* A sequence number of a drink */
CONSTRAINT ORDERS_PKEY PRIMARY KEY(DRINKER, PUB, ODATE, DRINK, DRINK_NO),
CONSTRAINT ORDERS_FKEY1 FOREIGN KEY(PUB, DRINK) REFERENCES SERVES(PUB, DRINK),
CONSTRAINT ORDERS_FKEY2 FOREIGN KEY(DRINKER) REFERENCES DRINKERS(DRINKER) );
CREATE TABLE LOCATED( /* Pubs have locations */
PUB VARCHAR(30) NOT NULL, /* Pub name */
STREET VARCHAR(30) NOT NULL, /* Street name */
BLDG_NO DECIMAL(4) NOT NULL, /* Building number */
CONSTRAINT LOCATED_PKEY PRIMARY KEY(PUB) );
到目前为止是我的SELECT语句:
SELECT DISTINCT DRINKER
FROM ORDERS
WHERE EXISTS (SELECT PUB
FROM LOCATED
WHERE STREET = 'VICTORIA AVE.'
AND ORDERS.ODATE >= STR_TO_DATE('01-MAR-2020','%d-%M-%Y')
AND ORDERS.ODATE <= STR_TO_DATE('01-MAR-2020','%d-%M-%Y'));
这不适用于EXISTS
。您需要与ORDERS
中的酒吧匹配的酒吧,因此您应该使用JOIN
或IN
SELECT DISTINCT o.drinker
FROM orders AS o
JOIN located AS l ON o.pub = l.pub
WHERE l.STREET = 'VICTORIA AVE.'
AND o.ODATE BETWEEN STR_TO_DATE('01-MAR-2020','%d-%M-%Y') AND STR_TO_DATE('01-MAR-2020','%d-%M-%Y'));