how to array_rand an array?

Question

I have 1 table. I would like to create an small lottery game.

t1 have data as below.

+---------+------------------+-------------------+
| ID      | typeid           | createtime        |
+---------+------------------+-------------------+
| 1       | 1                | 123456            |
| 2       | 2                | 123123            |
| 3       | 1                | 12312312312       |
| 4       | 1                | 13123123          |
| 5       | 1                | 123dddddaasd123   |
+------------------------------------------------+

I would like to choose the winner when the typeid = 1.

My query like this (actually use query or fetch_all of fetch_first?)

$qsid = DB::fetch_all("SELECT * FROM ".DB::table('t1')." WHERE typeid = 1");

and I would like to use

array_rand to choose winner, so should be like array_rand(1,3,4,5);

then I can use the final result to set the winner. Or any suggestion for other better way?

Thank you.

Bhavik Hirani · Accepted Answer · 2016-08-07 05:10:22Z

3

Try This New One

SELECT `ID` 
FROM `t1` 
WHERE `ID` IN (
               SELECT `ID` 
               FROM `t1` 
               WHERE `typeid` = 1)
ORDER BY RAND()
LIMIT 1

answered Aug 7, 2016 at 5:10

Bhavik Hirani

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4 Comments

Swee Hong Over a year ago

Thank you. but my DB:: function was not allow me for SELECT in a SELECT for query safety issue, anyway, the ORDER BY RAND() is what I need, thank you !

Bhavik Hirani Over a year ago

try this $select = $db->select()->from(array('t' => 't1'),array('ID')) ->where("WHERE ID IN (SELECT ID FROM t1 WHERE typeid = 1)") ->order('ORDER BY RAND()') ->limit('LIMIT 1');

sanjeevjha Over a year ago

actually we can do it multiple ways but we need to keep in mind about performance inner query is less optmised rather that single query

Bhavik Hirani Over a year ago

ya i know but i only just simply guide you that your query will be like this ,then you have to modify your query depend on your requirement.i just guide as like your Question. so don't forget to accept it / up vote it (click on the little greyed check mark / Up arrow beside this answer). Thanks

sanjeevjha · Accepted Answer · 2016-08-07 03:52:16Z

2

We can do it in various way, let's do it as below.

1st way: let's do it on mysql level

select ID from t1 where typeid =1 order by RAND() limit 1;

above query will select random row of mysql where typeid is 1.

2nd way:let's do it on coding level

we need to select ID from t1 where typeid =1 and keep it in any array and then select random element from the array

int array[]={1,3,4,5}
int finalResultId = array[java.util.new Random().nextInt(array.length)]

I hope it will help you out. Thanks

answered Aug 7, 2016 at 3:52

sanjeevjha

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1 Comment

Swee Hong Over a year ago

I think the order by RAND() limit 1; is already enough for me, thank you!

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