, , LIMIT, .
5 "news" "id" 5:
SELECT * FROM `news` WHERE `id` > 5 LIMIT 5;
ORDER BY. ( , ). : (ASC, ) (DESC).
10 "news" "id" 5, ("author") , ("id") :
SELECT * FROM `news` WHERE `id` > 5 ORDER BY `author` ASC, `id` DESC LIMIT 10;
( )
1. AVG(). , . ("id") :
SELECT AVG(`id`) FROM `news`;
2. MIN() MAX() . , . ("id") :
SELECT MIN(`id`), MAX(`id`) FROM `news`;
3. SUM(). , . ("id") :
SELECT SUM(`id`) FROM `news`;
4. COUNT(). , . , , , (*). "news":
SELECT COUNT(*) FROM `news`;
DISTINCT, , . , :
|
|
SELECT COUNT(DISTINCT `author`) FROM `news`;
GROUP BY. - , , - .
( ), ( , ).
"news" "author":
SELECT * FROM `news` GROUP BY `author`;
, , , :
SELECT `author`, COUNT(*) FROM `news` GROUP BY `author`;
GROUP BY HAVING, WHERE, .
, HAVING , , 3 :
SELECT `author`, COUNT(*) AS `cnt` FROM `news` GROUP BY `author` HAVING `cnt` > 3;