如何從多個表中選擇多個值？

Question

我想SELECT SELECT PROJECT_ID，STAFF_ID，HARDWARE_ID和SOFTWARE_ID都鏈接在一個表ASSIGNMENTS中，但我想顯示該鏈接，同時還顯示鏈接到相關ID（例如STAFF_NAME，JOB_TYPE，來自STAFF表的JOB_GRADE）。這裏是我的代碼：

CREATE TABLE PROJECT 
(PROJECT_ID CHAR(5) NOT NULL, 
PROJECT_NAME CHAR(20), 
PROJECT_TYPE CHAR(20), 
START_DATE DATE, 
END_DATE DATE, 
PRIMARY KEY (PROJECT_ID)); 

CREATE TABLE HARDWARE 
(HARDWARE_ID CHAR(5) NOT NULL, 
HARDWARE_NAME CHAR(20), 
PRIMARY KEY (HARDWARE_ID)); 

CREATE TABLE SOFTWARE 
(SOFTWARE_ID CHAR(5) NOT NULL, 
SOFTWARE_NAME CHAR(20), 
PRIMARY KEY (SOFTWARE_ID)); 

CREATE TABLE STAFF 
(STAFF_ID CHAR(5) NOT NULL, 
STAFF_NAME CHAR(20), 
JOB_TYPE CHAR(20), 
JOB_GRADE CHAR(20), 
PRIMARY KEY (STAFF_ID)); 

CREATE TABLE ASSIGNMENTS 
(ASSIGNMENT_ID CHAR(5) NOT NULL, 
PROJECT_ID CHAR(5), 
STAFF_ID CHAR(5), 
HARDWARE_ID CHAR(5), 
SOFTWARE_ID CHAR(5), 
PRIMARY KEY (ASSIGNMENT_ID), 
FOREIGN KEY (PROJECT_ID) REFERENCES PROJECT(PROJECT_ID), 
FOREIGN KEY (STAFF_ID) REFERENCES STAFF(STAFF_ID), 
FOREIGN KEY (HARDWARE_ID) REFERENCES HARDWARE(HARDWARE_ID), 
FOREIGN KEY (SOFTWARE_ID) REFERENCES SOFTWARE(SOFTWARE_ID)); 

下面是一些基本的數據：

INSERT INTO PROJECT (PROJECT_ID, PROJECT_NAME, PROJECT_TYPE, START_DATE, END_DATE) 
VALUES ('B0001','BIKESHOP.COM','WEB DEVELOPMENT',TO_DATE('15/01/17','DD/MM/YY'),TO_DATE('15/02/17','DD/MM/YY')); 

INSERT INTO HARDWARE (HARDWARE_ID, HARDWARE_NAME) 
VALUES ('H0001','WEBDEV PC1'); 

INSERT INTO SOFTWARE (SOFTWARE_ID, SOFTWARE_NAME) 
VALUES ('S0001','COFFEECUP IDE'); 

INSERT INTO STAFF (STAFF_ID, STAFF_NAME, JOB_TYPE, JOB_GRADE) 
VALUES ('ST001','JOHN MASON','WEB DEVELOPER','1'); 

INSERT INTO ASSIGNMENTS (ASSIGNMENT_ID, PROJECT_ID, STAFF_ID, HARDWARE_ID, SOFTWARE_ID) 
VALUES ('A0001','B0001','ST001','H0001','S0001'); 

我如何可以選擇鏈接到一個PROJECT_ID所有表的所有屬性，以顯示例如：

PROJECT_ID, PROJECT_NAME, PROJECT_TYPE, START_DATE, END_DATE, STAFF_ID, STAFF_NAME, JOB_TYPE, JOB_GRADE, HARDWARE_ID, HARDWARE_NAME, SOFTWARE_ID, SOFTWARE_NAME 
as one row, all linked to PROJECT_ID = 'B0001'. 

Answer 1

我明白了，你需要爲你精確的查詢拼寫出來。這裏你去：

select p.*, 
    s.*, 
    h.*, 
    sf.* 
from assignments a 
inner join staff s on a.staff_id = s.staff_id 
inner join software sf on a.software_id = sf.software_id 
inner join hardware h on a.hardware_id = h.hardware_id 
inner join project p on a.project_id = p.project_id 
where a.project_id = 'A0001';