Data cleaning: Difference between revisions
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* Google spreadsheet: | * Google spreadsheet: | ||
** [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 cell value is exactly {{kbd | key = NULL}} not {{kbd | key = #NULL!}}, You may use {{kbd | key = <nowiki>EXACT(value, "NULL")</nowiki>}} | ||
* MySQL SQL syntax: {{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> | * MySQL SQL syntax: {{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> | ||
Revision as of 18:46, 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 cell value is exactly NULL not #NULL!, You may use EXACT(value, "NULL")
- MySQL SQL syntax: SELECT * FROM table WHERE column IS NULL;[1]
Finds whether a variable is NOT NULL
- MySQL SQL syntax: SELECT * FROM table WHERE column IS NOT NULL;