如何從SQL數據庫表中獲取數據
您可以使用SELECT
命令從表中獲取數據。
獲取所有行和列:
SELECT * FROM people;
age | name
-----+--------
37 | Flavio
8 | Roger
只獲取name
列:
SELECT name FROM people;
name
--------
Flavio
Roger
計算表中的項目數量:
SELECT COUNT(*) from people;
count
-------
2
您可以使用WHERE
子句過濾表中的行:
SELECT age FROM people WHERE name='Flavio';
age
-----
37
查詢的結果可以按列值升序(默認)或降序使用ORDER BY進行排序:
SELECT * FROM people ORDER BY name;
SELECT * FROM people ORDER BY name DESC;