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Databases Reporting with SQL Working with Text Creating Excerpts From Text

Concatenate empty data


How do I write my query if I'm using concatenation with two columns, say for instance, first_name and last_name, and there are empty cells for some last_name?


Are you talking about empty or null? If null the default behavior is to return null when concatenating values (depending on the data engine and settings used).

I just tried in the playground and found this to be the case. Open the playground for the video and run the following

SELECT typeof(first_name || last_name) AS myname FROM customers WHERE last_name IS NULL;
UPDATE customers SET last_name = '' WHERE last_name IS NULL; 
SELECT first_name || last_name AS myname FROM customers WHERE last_name = '';

The first select returns null for the concatenated fields

The update statement updates null last_names to empty

The second select returns the first name and an empty string for the concatenated fields

1 Answer

They'll just be empty unless you want to filter or replace the empty value somehow

Hi Thanks for your response. When I tried it came back with both empty, even though there was a first name.