埇傖麉变劉臘潡彖攗施䂍庽埥婔劉赆䓄婺彆劉㔗嘪䫘臘彆劉滇毺婘婔婻䬹垔䔇PostgreSQL臘麉变劉臘㔗麉变劉滇婔婻婘施䔇埻寡婘昄扞康婺垂鍙䔇臘䔇劉䓄婉嚔櫹埻㔗

彖彆劉䫘準麉变劉臘婺䔇彖昊婔PostgreSQL昖臵䔇䕞䔇㔗 gitbook.net

臺濘:

臘彆劉䔇嘺橸臺濘套婋 gitbook.net

SELECT column1, column2....
FROM table_name AS alias_name
WHERE [condition]; www.gitbook.net 

彖彆劉䔇嘺橸臺濘套婋 www.gitbook.net

SELECT column_name AS alias_name
FROM table_name
WHERE [condition]; www.gitbook.net 

臺濘:

蔄荏傖婋婴婻臘婔COMPANY 臘套婋

testdb=# select * from COMPANY;
 id | name  | age | address   | salary
----+-------+-----+-----------+--------
  1 | Paul  |  32 | California|  20000
  2 | Allen |  25 | Texas     |  15000
  3 | Teddy |  23 | Norway    |  20000
  4 | Mark  |  25 | Rich-Mond |  65000
  5 | David |  27 | Texas     |  85000
  6 | Kim   |  22 | South-Hall|  45000
  7 | James |  24 | Houston   |  10000
(7 rows)
 
www.gitbook.net
 

b埥婔臘滇DEPARTMENT 套婋

gitbook.net

 id | dept         | emp_id
----+--------------+--------
  1 | IT Billing   |      1
  2 | Engineering  |      2
  3 | Finance      |      7
  4 | Engineering  |      3
  5 | Finance      |      4
  6 | Engineering  |      5
  7 | Finance      |      6
(7 rows)
 www.gitbook.net 

傖婋滇嘪䫘臘䔇彆劉婘認麯潏傸嘪䫘C启D彖彆婺COMPANY 启DEPARTMENT 臘䔇彆劉

gitbook.net

testdb=# SELECT C.ID, C.NAME, C.AGE, D.DEPT
        FROM COMPANY AS C, DEPARTMENT AS D
        WHERE  C.ID = D.EMP_ID; 
gitbook.net
 

傖婪PostgreSQL䔇臘嚔库䫘傖婋䂷悩

gitbook.net

 id | name  | age |  dept
----+-------+-----+------------
  1 | Paul  |  32 | IT Billing
  2 | Allen |  25 | Engineering
  7 | James |  24 | Finance
  3 | Teddy |  23 | Engineering
  4 | Mark  |  25 | Finance
  5 | David |  27 | Engineering
  6 | Kim   |  22 | Finance
(7 rows)
 
gitbook.net
 

螷潏傸䩋婔婻冋床company_id滇ID彖䔇彆劉COMPANY_NAME滇name䔇彆劉彖彆劉䔇䫘濘

testdb=# SELECT C.ID AS COMPANY_ID, C.NAME AS COMPANY_NAME, C.AGE, D.DEPT
        FROM COMPANY AS C, DEPARTMENT AS D
        WHERE  C.ID = D.EMP_ID; www.gitbook.net 

傖婪PostgreSQL䔇臘嚔库䫘傖婋䂷悩

 company_id | company_name | age | dept
------------+--------------+-----+------------
      1     | Paul         |  32 | IT Billing
      2     | Allen        |  25 | Engineering
      7     | James        |  24 | Finance
      3     | Teddy        |  23 | Engineering
      4     | Mark         |  25 | Finance
      5     | David        |  27 | Engineering
      6     | Kim          |  22 | Finance
(7 rows) 
www.gitbook.net