select 1 random number from mysql database using asp.net c# -


how can select 1 random number database thats id autoincrement field.i have 25,000[id] records in database.each every time select 1 new random id. how can it.

use following sql(slow)

'select * tablename order rand() limit 1'

or can use(fast)

select * mytable, (select floor(max(mytable.id) * rand()) randid mytable) somerandid mytable.id = somerandid.randid

the inner select gives random id in right range. outer select looks right row in table.


Comments

Post a Comment

Popular posts from this blog

How to connect android app to App engine -

i'm trying connect app in android server i've opened on appengine. my server's name : dddd-daniel-2345 , website server : http://dddd-daniel-2345.appspot.com/ this how connect android app server in app engine: app.yaml: application: dddd-daniel-2345 version: 1 runtime: python27 api_version: 1 threadsafe: yes handlers: - url: .* script: main.app libraries: - name: webapp2 version: "2.5.2" main.py: #!/usr/bin/env python # # copyright 2007 google inc. google.appengine.api import users import webapp2 class userhandler(webapp2.requesthandler): def get(self): user = users.get_current_user() if user: greeting = ('%s,%s,%s' % (user.email(),user.user_id(),user.nickname())) else: greeting = ('not logged in') self.response.out.write(greeting) app = webapp2.wsgiapplication([('/', userhandler),], debug=true) my applications code : add manifast main....
Read more

gcc - MinGW's ld cannot perform PE operations on non PE output file -

i know there other similar questions out there, stackoverflow or not. i've researched lot this, , still didn't find single solution. i'm doing operative system side project. i've been doing in assembly, wanna join c code. test, made assembly code file (called test.asm): [bits 32] global _a section .text _a: jmp $ then made c file (called main.c): extern void a(void); int main(void) { a(); } to link, used file (called make.bat): "c:\mingw\bin\gcc.exe" -ffreestanding -c -o c.o main.c nasm -f coff -o asm.o test.asm "c:\mingw\bin\ld.exe" -ttext 0x100000 --oformat binary -o out.bin c.o asm.o pause i've been researching ages, , i'm still struggling find answer. hope won't flagged duplicate. acknowledge existence of similar questions, have different answers, , none work me. question: what doing wrong? old mingw versions had problem "ld" not able create non-pe files @ all. maybe current versions...
Read more

php - display validation error message next to the textbox in codeigniter -

Image
i'm newbie codeigniter.i want display error message next text box.my view file create.php contains following code. <?php echo validation_errors(); //validation echo form_open('news/create'); //create form ?> <div class="boxes"> <div class="common"> <div class="lables"> <label for="name">name</label> </div> <div class="text_boxes"> <input type="text" name="uname" /><div id="infomessage"><?php echo $message;?></br> </div> </div>` and below controller model: public function create() { $this->load->helper('form'); $this->load->library('form_validation'); $data['title'] = 'insert items'; $this->form_validation->set_rules('uname','required|min_length[6]|m...
Read more