Data cleaning: Difference between revisions
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== check if field value was not fulfilled: NULL, empty value == | == check if field value was not fulfilled: NULL, empty value == | ||
# {{kbd | key = NULL}} value: {{kbd | key = SELECT * FROM table_name WHERE column_name IS NULL;}} | # {{kbd | key = NULL}} value: {{kbd | key = SELECT * FROM table_name WHERE column_name IS NULL;}} | ||
# empty value: {{kbd | key = SELECT * FROM table_name WHERE LENGTH(TRIM( column_name )) = 0;}} | # empty value: {{kbd | key = SELECT * FROM table_name WHERE LENGTH(TRIM( column_name )) = 0;}} {{exclaim}} SQL query with the condition {{kbd | key =SELECT * FROM table_name WHERE column_name IS NOT NULL}} includes empty value | ||
== check if field contains value == | == check if field contains value == | ||
Revision as of 17:11, 27 February 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] demo
Finds whether a variable is NOT NULL
- MySQL SQL syntax: SELECT * FROM table WHERE column IS NOT NULL; demo
check if field value was not fulfilled: NULL, empty value
- NULL value: SELECT * FROM table_name WHERE column_name IS NULL;
- empty value: SELECT * FROM table_name WHERE LENGTH(TRIM( column_name )) = 0;
SQL query with the condition SELECT * FROM table_name WHERE column_name IS NOT NULL includes empty value
check if field contains value
(left blank intentionally)