sql - Account for NULL and Blank as being different in comparison (issue caused by ISNULL function) -


i'm looking best practices here far checking equality fields may null or blank. example, if i'm doing comparison such

a.field01 != b.field01 in clause, know need account nulls if ansi_nulls on, such as: isnull(a.field01,'') != isnull(b.field01,'') in order cases 1 of fields null , other not. however, since database i'm working has blank fields in addition nulls (ugh), i'd comparison distinguishes between null , blank, intend use in update script update accordingly (and set destination column null). above comparison, if 1 field blank ('') , other null, row not evaluated being different. best practice here make suret following results returned:

a.field01 (null) != b.field01 (blank) a.field01 (blank) != b.field01 (blank) a.field01 (null) != b.field01 (non-null / blank) a.field01 (non-null / blank) != b.field01 (null)

sorry if of confusing or poorly communicated. let me know , i'll try explain better if that's case!

i'm not sure confusion lies. if want not-equals between 2 fields, should do:

a.field01 <> b.field01

if either (or both) values null, evaluates null treated false. seems logic want.

if want blanks treated null (which on closer reading seems desire), then:

nullif(a.field01, '') <> nullif(b.filed01, '')

Comments

Post a Comment

Popular posts from this blog

sublimetext3 - what keyboard shortcut is to comment/uncomment for this script tag in sublime -

Image
i have script tag in code, keyboard shortcut comment/uncomment script tag in sublime. after selecting script open , close tag. <script src="http://code.jquery.com/jquery-latest.min.js" type="text/javascript"> </script> i pressing ctrl + shift + / , getting this /*<script src="http://code.jquery.com/jquery-latest.min.js" type="text/javascript"> </script>*/ also pressed ctrl + / , got this // <script src="http://code.jquery.com/jquery-latest.min.js" type="text/javascript"> // </script> instead of <!-- <script src="http://code.jquery.com/jquery-latest.min.js" type="text/javascript"> </script> --> script open , close tag in 2 lines not in 1 line , not have spaces too. for mac,high light lines want comment. hold 'command , / ' commented. for windows: high line or select lines ,then hold ctrl + / if not work: ...
Read more

java - No use of nillable="0" in SOAP Webservice -

i have received xsd 3rd party supplier generated java based system; used create soap endpoint receive data transfers. xsd not make use of nillable attribute defined within w3c/xsd namespace, example: <xs:complextype name="customer"> <xs:sequence> <xs:element minoccurs="1" maxoccurs="1" name="id" type="xs:integer"/> <xs:element minoccurs="0" maxoccurs="1" name="titleid" type="xs:integer"/> <xs:element minoccurs="0" maxoccurs="1" name="firstname" type="xs:string"/> <xs:element minoccurs="0" maxoccurs="1" name="familyname" type="xs:string"/> <xs:element minoccurs="0" maxoccurs="1" name="previousname" type="xs:string"/> <xs:element minoccurs="0" maxoccurs="1" nam...
Read more

ubuntu - Laravel 5.2 quickstart guide gives Not Found Error -

edit: think problem due not setting apache properly, these 2 links helped me. solution: http://laravel.io/forum/06-11-2014-not-found-but-route-exists https://www.digitalocean.com/community/tutorials/how-to-set-up-apache-virtual-hosts-on-ubuntu-14-04-lts end edit i'm following laravel 5.2 quickstart guide. https://laravel.com/docs/5.2/quickstart i'm running ubuntu 14.04.2 the website runs initially, when click on add task button run 404 not found error. as per guide run following commands setup complete quickstart project. git clone https://github.com/laravel/quickstart-basic quickstart cd quickstart composer install php artisan migrate additionally run following commands because i'm on ubuntu server: sudo chown -r www-data.www-data quickstart sudo chmod -r 755 quickstart sudo chmod 777 quickstart/storage the routes.php file looks like: <?php use app\task; use illuminate\http\request; route::group(['middleware' => ['web']]...
Read more