218. Distinguishing empty strings and NULL values

There’s one more thing I’d like you to think about before we move to regular expressions and string functions.

When we filter data in text columns we usually expect that the text value is either present or it is NULL (no value). Usually, it is the case, but it could also happen that the text value is an empty strings '' (technically, also no value). 💣

Empty strings could introduce ambiguity in our reports, if not handled correctly. For example, if we want to measure the success of the profile feature we can calculate the percentage of profiles...

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Hi, it’s Anatoli, the author of SQL Habit. 👋

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