Posted over 11 years ago. Visible to the public. Repeats.

MySQL: CONCAT with NULL fields

In MySQL,

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CONCAT('foo', 'bar', NULL) = NULL

the NULL always wins in MySQL.

If you would rather treat NULL as an empty string, use CONCAT_WS Archive (concatenation with separator) instead:

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CONCAT_WS('', 'foo', 'bar', NULL) = 'foobar'

PostgreSQL

In PostgreSQL the NULL is not viral in CONCAT:

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CONCAT('foo', 'bar', NULL) = 'foobar'

Does your version of Ruby on Rails still receive security updates?
Rails LTS provides security patches for unsupported versions of Ruby on Rails (2.3, 3.2, 4.2 and 5.2).

Owner of this card:

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Tobias Kraze
Last edit:
almost 4 years ago
by Thomas Eisenbarth
About this deck:
We are makandra and do test-driven, agile Ruby on Rails software development.
License for source code
Posted by Tobias Kraze to makandra dev
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