Data cleaning: Difference between revisions
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== is null == | |||
Finds whether a variable is NULL | Finds whether a variable is NULL | ||
* PHP [http://tw2.php.net/is_null is_null] | * PHP [http://tw2.php.net/is_null is_null] | ||
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** [https://support.google.com/drive/answer/3093348 ISERR(value)] " value - The value to be verified as an error type other than #N/A." ex: {{kbd | key = #NULL!}} | ** [https://support.google.com/drive/answer/3093348 ISERR(value)] " value - The value to be verified as an error type other than #N/A." ex: {{kbd | key = #NULL!}} | ||
** If the value is exactly {{kbd | key = NULL}} not {{kbd | key = #NULL!}}, You may use {{kbd | key = <nowiki>EXACT(value, "NULL")</nowiki>}} | ** If the value is exactly {{kbd | key = NULL}} not {{kbd | key = #NULL!}}, You may use {{kbd | key = <nowiki>EXACT(value, "NULL")</nowiki>}} | ||
* MySQL {{kbd | key = SELECT * FROM table WHERE column IS NULL;}}<ref>[http://dev.mysql.com/doc/refman/5.0/en/working-with-null.html MySQL :: MySQL 5.0 Reference Manual :: 3.3.4.6 Working with NULL Values]</ref> | |||
== references == | |||
<references/> | |||
[[Category:Spreadsheet]] | [[Category:Spreadsheet]] | ||
Revision as of 18:28, 8 January 2014
is null
Finds whether a variable is NULL
- PHP is_null
- Google spreadsheet:
- ISERR(value) " value - The value to be verified as an error type other than #N/A." ex: #NULL!
- If the value is exactly NULL not #NULL!, You may use EXACT(value, "NULL")
- MySQL SELECT * FROM table WHERE column IS NULL;[1]