我需要确保下面列出的查询被实现为具有EXISTS / NOT EXISTS子句的嵌套查询。
“查找在2017年至少进行过一次旅行的司机的名字和姓氏。”
到目前为止是我的代码：
SELECT EMPLOYEE.FNAME, EMPLOYEE.LNAME
FROM EMPLOYEE
WHERE EXISTS
(SELECT ENUM FROM DRIVER WHERE EMPLOYEE.ENUM=DRIVER.ENUM) AND
(SELECT LNUM FROM TRIP WHERE TRIP.LNUM=DRIVER.LNUM AND
YEAR(TDATE)=2017);
我不确定这是语法错误还是输入的值错误。但是，我三重检查了所有值，它们似乎与表数据匹配。
以下列出了表格：
CREATE TABLE TRIP(
TNUM DECIMAL(10) NOT NULL,
LNUM DECIMAL(8) NOT NULL,
REGNUM VARCHAR(10) NOT NULL,
TDATE DATE NOT NULL,
CONSTRAINT TRIP_PKEY PRIMARY KEY (TNUM),
CONSTRAINT TRIP_CKEY UNIQUE (LNUM, REGNUM, TDATE),
CONSTRAINT TRIP_FKEY1 FOREIGN KEY (LNUM) REFERENCES DRIVER(LNUM),
CONSTRAINT TRIP_FKEY2 FOREIGN KEY (REGNUM) REFERENCES TRUCK(REGNUM) );
CREATE TABLE DRIVER(
ENUM DECIMAL(12) NOT NULL,
LNUM DECIMAL(8) NOT NULL,
STATUS VARCHAR(10) NOT NULL,
CONSTRAINT DRIVER_PKEY PRIMARY KEY(ENUM),
CONSTRAINT DRIVER_UNIQUE UNIQUE(LNUM),
CONSTRAINT DRIVER_FKEY FOREIGN KEY(ENUM) REFERENCES EMPLOYEE(ENUM),
CONSTRAINT DRIVER_STATUS CHECK ( STATUS IN ('AVAILABLE', 'BUSY', 'ON
LEAVE')) );
CREATE TABLE EMPLOYEE(
ENUM DECIMAL(12) NOT NULL,
FNAME VARCHAR(50) NOT NULL,
INITIALS VARCHAR(5) NULL,
LNAME VARCHAR(50) NOT NULL,
DOB DATE NULL,
BLDG DECIMAL(3) NOT NULL,
STREET VARCHAR(50) NOT NULL,
SUBURB VARCHAR(50) NOT NULL,
STATE VARCHAR(5) NOT NULL,
ZIPCODE DECIMAL(4) NOT NULL,
CONSTRAINT EMPLOYEE_PKEY PRIMARY KEY(ENUM) );
以下列出了表格数据：
INSERT INTO TRIP VALUES( 1, 10001, 'PKR768', '2015-01-12' );
INSERT INTO TRIP VALUES( 2, 10001, 'SYF777', '2015-02-20' );
INSERT INTO TRIP VALUES( 3, 10001, 'KKK007', '2015-03-12' );
INSERT INTO TRIP VALUES( 4, 10001, 'PKR768', '2015-06-29' );
INSERT INTO TRIP VALUES( 5, 20002, 'PKR768', '2015-01-12' );
INSERT INTO TRIP VALUES( 6, 10002, 'SYF777', '2015-02-20' );
INSERT INTO TRIP VALUES( 7, 30005, 'KKK007', '2015-03-12' );
INSERT INTO TRIP VALUES( 8, 10001, 'PKR768', '2015-01-13' );
INSERT INTO TRIP VALUES( 9, 10002, 'QRT834', '2015-09-17' );
INSERT INTO TRIP VALUES(10, 30005, 'KKK007', '2015-12-15' );
INSERT INTO TRIP VALUES(11, 10003, 'SST005', '2016-01-23' );
INSERT INTO TRIP VALUES(12, 10002, 'PKR768', '2016-03-12' );
INSERT INTO TRIP VALUES(13, 20002, 'QRT834', '2015-04-23' );
INSERT INTO TRIP VALUES(14, 20002, 'PKR008', '2015-04-23' );
INSERT INTO TRIP VALUES(15, 30005, 'PKR768', '2015-05-24' );
INSERT INTO TRIP VALUES(16, 30005, 'SST005', '2014-08-02' );
INSERT INTO TRIP VALUES(17, 20002, 'QRT834', '2014-09-17' );
INSERT INTO TRIP VALUES(18, 10001, 'KKK007', '2014-12-15' );
INSERT INTO TRIP VALUES(19, 30005, 'SST005', '2016-01-23' );
INSERT INTO TRIP VALUES(20, 10003, 'PKR768', '2016-03-12' );
INSERT INTO TRIP VALUES(21, 10001, 'QRT834', '2012-04-23' );
INSERT INTO TRIP VALUES(22, 30005, 'PKR008', '2012-04-23' );
INSERT INTO TRIP VALUES(23, 10003, 'PKR768', '2012-05-25' );
INSERT INTO TRIP VALUES(24, 20002, 'SST005', '2012-08-02' );
INSERT INTO TRIP VALUES(25, 10001, 'PKR768', '2014-01-12' );
INSERT INTO TRIP VALUES(26, 10001, 'SYF777', '2013-02-20' );
INSERT INTO TRIP VALUES(27, 20002, 'KKK007', '2013-03-12' );
INSERT INTO TRIP VALUES(28, 30005, 'PKR768', '2010-06-29' );
INSERT INTO TRIP VALUES(29, 10001, 'QRT834', '2010-09-17' );
INSERT INTO TRIP VALUES(30, 10002, 'KKK007', '2010-12-15' );
INSERT INTO TRIP VALUES(31, 10003, 'SST005', '2010-01-23' );
INSERT INTO TRIP VALUES(32, 20002, 'PKR768', '2010-03-12' );
INSERT INTO TRIP VALUES(33, 30005, 'QRT834', '2003-04-23' );
INSERT INTO TRIP VALUES(34, 30005, 'PKR008', '2004-04-23' );
INSERT INTO TRIP VALUES(35, 10001, 'PKR768', '2017-05-24' );
INSERT INTO DRIVER VALUES( 1, 10001, 'AVAILABLE' );
INSERT INTO DRIVER VALUES( 2, 10008, 'ON LEAVE' );
INSERT INTO DRIVER VALUES( 3, 10002, 'AVAILABLE' );
INSERT INTO DRIVER VALUES( 4, 10004, 'AVAILABLE' );
INSERT INTO DRIVER VALUES( 5, 10003, 'ON LEAVE' );
INSERT INTO DRIVER VALUES( 6, 10012, 'AVAILABLE' );
INSERT INTO DRIVER VALUES( 7, 20002, 'BUSY' );
INSERT INTO DRIVER VALUES( 8, 20003, 'BUSY' );
INSERT INTO DRIVER VALUES( 9, 30005, 'BUSY' );
INSERT INTO DRIVER VALUES( 10, 40002, 'BUSY' );
INSERT INTO DRIVER VALUES( 11, 20045, 'AVAILABLE' );
INSERT INTO DRIVER VALUES( 12, 20055, 'AVAILABLE' );
INSERT INTO DRIVER VALUES( 13, 20065, 'AVAILABLE' );
INSERT INTO DRIVER VALUES( 14, 10305, 'AVAILABLE' );
INSERT INTO DRIVER VALUES( 15, 10345, 'AVAILABLE' );
INSERT INTO DRIVER VALUES( 16, 10705, 'AVAILABLE' );
INSERT INTO DRIVER VALUES( 17, 40005, 'AVAILABLE' );
INSERT INTO EMPLOYEE VALUES( 1, 'John', NULL, 'Smith', NULL, 42,
'Victoria St.', 'Hurstville', 'NSW', 2456 );
INSERT INTO EMPLOYEE VALUES( 2, 'Peter', NULL, 'Taylor', '1970-01-
12', 42, 'Victoria St.', 'Hurstville', 'NSW', 2456 );
INSERT INTO EMPLOYEE VALUES( 3, 'John', NULL, 'Doe', '1966-03-23',
12, 'Station St.', 'Dapto', 'NSW', 2530 );
INSERT INTO EMPLOYEE VALUES( 4, 'John', NULL, 'Gray', '1988-05-05',
16, 'Station St.', 'Dapto', 'NSW', 2530 );
INSERT INTO EMPLOYEE VALUES( 5, 'Adam', NULL, 'Taylor', '1980-01-01',
42, 'Church St.', 'City', 'NSW', 2300 );
INSERT INTO EMPLOYEE VALUES( 6, 'Michael', NULL, 'Jones', '1975-03-
05', 23, 'Waterloo Ave.', 'Surry Hills', 'NSW', 2502 );
INSERT INTO EMPLOYEE VALUES( 7, 'Frederic', NULL, 'Jones', NULL, 3,
'Victoria St.', 'Redfern', 'NSW', 2420 );
INSERT INTO EMPLOYEE VALUES( 8, 'Peter', NULL, 'O''Brien', '1983-02-
28', 19, 'Lucas Dr.', 'Horsley', 'NSW', 2530 );
INSERT INTO EMPLOYEE VALUES( 9, 'John', NULL, 'Lucas', '1966-12-16',
20, 'Huxley St.', 'Horsley', 'NSW', 2530 );
INSERT INTO EMPLOYEE VALUES( 10, 'John', NULL, 'Fox', '1975-10-15',
18, 'Victoria St.', 'Hurstville', 'NSW', 2456 );
INSERT INTO EMPLOYEE VALUES( 11, 'Adam', NULL, 'Fox', NULL, 45,
'Victoria St.', 'Hurstville', 'NSW', 2456 );
INSERT INTO EMPLOYEE VALUES( 12, 'Phillip', NULL, ',Cox', '1984-12-
12', 5, 'The Avenue', 'Rockdale', 'NSW', 2300 );
INSERT INTO EMPLOYEE VALUES( 13, 'Andrew', 'K', 'Smith', '1969-04-
04', 42, 'Bambaramba Ave.', 'Pennant Hills', 'NSW', 2556 );
INSERT INTO EMPLOYEE VALUES( 14, 'Andrew', 'R', 'Smith', '1992-04-
01', 67, 'King Cr.', 'Hurstville', 'NSW', 2456 );
INSERT INTO EMPLOYEE VALUES( 15, 'Michael', NULL, 'Potter', '1995-04-
01', 568, 'Bong Bong St.', 'Horsley', 'NSW', 2530 );
INSERT INTO EMPLOYEE VALUES( 16, 'Harry', NULL, 'Potter', '1995-04-
01', 568, 'Bong Bong St.', 'Horsley', 'NSW', 2530 );
INSERT INTO EMPLOYEE VALUES( 17, 'James', NULL, 'Bond', NULL, 007,
'Alan Bond St.', 'Perth', 'WA', 6000 );
INSERT INTO EMPLOYEE VALUES( 18, 'Paris', NULL, 'Hilton', NULL, 1,
'Hilton St.', 'Melbourne', 'Vic', 3000 );
INSERT INTO EMPLOYEE VALUES( 19, 'Lady', NULL, 'Gaga', NULL, 3, 'Pork
st.', 'Hobart', 'Tas', 7000 );
INSERT INTO EMPLOYEE VALUES( 20, 'Robin', NULL, 'Hood', NULL, 6,
'Nottingham Pl.', 'Sydney', 'NSW', 2000 );
正确的语法是：
SELECT E.FNAME, E.LNAME
FROM EMPLOYEE E
WHERE EXISTS (SELECT 1
FROM DRIVER D
WHERE D.ENUM = E.ENUM
) AND
EXISTS (SELECT 1
FROM TRIP T
WHERE T.LNUM = E.LNUM AND YEAR(T.TDATE) = 2017
);
您需要重复EXISTS。另外：
SELECT的EXISTS中的值无关紧要。我使用1是因为它易于键入。YEAR()。标准语法为EXTRACT(YEAR FROM T.TDATE)。我认为您的数据库确实支持您正在使用的功能。DRIVERS（在现实世界中）进行比较。旅途中的驱动器不会自动成为“驱动器”吗？正确的语法是：
SELECT E.FNAME, E.LNAME
FROM EMPLOYEE E
WHERE EXISTS (SELECT 1
FROM DRIVER D
WHERE D.ENUM = E.ENUM
) AND
EXISTS (SELECT 1
FROM TRIP T
WHERE T.LNUM = E.LNUM AND YEAR(T.TDATE) = 2017
);
您需要重复EXISTS。另外：
SELECT的EXISTS中的值无关紧要。我使用1是因为它易于键入。YEAR()。标准语法为EXTRACT(YEAR FROM T.TDATE)。我认为您的数据库确实支持您正在使用的功能。DRIVERS（在现实世界中）进行比较。旅途中的驱动器不会自动成为“驱动器”吗？