MySQL產(chǎn)生隨機數(shù)？select round(round(rand()，4)*10000)不用函數(shù)直接這樣就好了。非得寫函數(shù)的話，就DELIMITER $$CREATE FUNCTION ge

MySQL產(chǎn)生隨機數(shù)？

select round(round(rand()，4)*10000)不用函數(shù)直接這樣就好了。非得寫函數(shù)的話，就DELIMITER $$CREATE FUNCTION get_rand() RETURNS INT DETERMINISTIC BEGIN DECLARE return_no INT SELECT ROUND(ROUND(RAND()，4)*10000) INTO return_no RETURN return_no END$$DELIMITER

mysql隨機查詢?nèi)舾蓷l數(shù)據(jù)的方法？

1.隨機讀取連續(xù)多條記錄。經(jīng)過實踐，可以隨機讀取多條連續(xù)的數(shù)據(jù)記錄，里頭取值的一般都是主鍵ID來進行最大值、最小值的讀取：

SELECT * FROM example_table AS t1 JOIN (SELECT ROUND(RAND() * ((SELECT MAX(id) FROM example_table)-(SELECT MIN(id) FROM example_table)) (SELECT MIN(id) FROM example_table)) AS id) AS t2 WHERE t1.id >= t2.id ORDER BY t1.id LIMIT 5

2.隨機多條數(shù)據(jù)。以下兩種都是隨機讀取數(shù)據(jù)，查詢數(shù)據(jù)速度、隨機范圍都基本相差不大

SELECT * FROM example_table WHERE id >= ((SELECT MAX(id) FROM example_table)-(SELECT MIN(id) FROM example_table)) * RAND() (SELECT MIN(id) FROM example_table) LIMIT 5

SELECT * FROM example_table WHERE id>=(SELECT floor(RAND() * ((SELECT MAX(id) FROM example_table)-(SELECT MIN(id) FROM example_table)) (SELECT MIN(id) FROM example_table))) ORDER BY id LIMIT 5

MYSQL隨機調(diào)取多個數(shù)值？

從1到1000范圍內(nèi)隨機一個數(shù)字mt_rand(1，1000)

查詢下這個數(shù)字 在這個表中的aid存不存在

用while去判斷下

$aidarr = array()

while (count($aidarr )

{

$randnum = mt_rand(1，1000)

$sql = "select count(aid) from dede_addonproducts where aid=$randnum"

$aid = $db->query($sql)

if ($aid == 1)

{

$aidarr[] = $randnum

}

}

這時候$aidarr還是數(shù)組不是字符串

然后用for 導(dǎo)入一下

for ($i=0$i

mysql如何生成不重復(fù)的隨機數(shù)？

mysql的rand函數(shù)可以生成一個0到1之間的隨機數(shù)，進行一定的放大即可得到一個隨機數(shù)。再通過條件查詢來限制新隨機數(shù)沒有在表中出現(xiàn)過。如下所示：

SELECT FLOOR(RAND() * 99999) AS random_numFROM numbers

WHERE "random_num" NOT IN (SELECT my_number FROM numbers)

LIMIT 1