以mysql自带的world数据库为例说明以下最常用
world结构
city结构
SELECT
选取
SELECT id,name
FROM WORLD.CITY
WHERE
条件
SELECT id,name,population
FROM WORLD.CITY
WHERE Population >= 600000
AND&OR
SELECT *
FROM WORLD.CITY
WHERE Population >= 600000 and countrycode = 'AUS';
SELECT *
FROM WORLD.CITY
WHERE Population >= 600000 or countrycode = 'AUS';
and&or
ORDER BY
可以针对数字排序 ,也可以对文本排序,甚至可以针对多个条件排序(以逗号,分隔)
SELECT *
FROM WORLD.CITY
WHERE Population >= 600000
ORDER BY population
以population从低到高排序
由高到低排序为
ORDER BY population desc
INSERT
插入
INSERT INTO world.city VALUES (19989,'test','AFG','kabol','100000');
INSERT INTO world.city (ID,NAME,COUNTRYCODE) VALUES (19899,'test','AFG')
UPDATE
UPDATE world.city SET id = 19898 WHERE id = 19899
DELETE
DELETE FROM world.city WHERE id = 19899