Data cleaning: Difference between revisions

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58 bytes added ,  4 March 2014
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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;}}
([http://sqlfiddle.com/#!2/9b01e/3/0 demo on sqlfiddle])
# {{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;}} {{exclaim}} SQL query with the condition {{kbd | key =SELECT * FROM table_name WHERE column_name IS NOT NULL}} includes empty value
# 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


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