Details
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Bug
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Status: Open (View Workflow)
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Minor
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Resolution: Unresolved
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10.3.15, 10.4.5, 10.6, 5.5(EOL), 10.1(EOL), 10.2(EOL), 10.3(EOL), 10.4(EOL), 10.5(EOL), 10.7(EOL), 10.8(EOL), 10.9(EOL), 10.10(EOL)
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MariaDB Docker (Bionic) on Ubuntu Linux 19.4
Description
Given the following, minimal sample:
CREATE SCHEMA A ; |
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CREATE TABLE A.A ( A BOOLEAN DEFAULT TRUE); |
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SELECT 1 AS A FROM A.A AS AA HAVING TRUE; |
Summary: No result is returned if a constant without aggregate function is selected and a HAVING clause (with a constant expression like 'TRUE'), without an explicit GROUP BY clause is used on an empty table.
I expect that a single 1 is returned. This is also the behaviour of Postgres and described here (https://stackoverflow.com/a/53238082). The HAVING groups the empty result into a single, but existing group. HAVING doesn't filter this single row, so a single row and result should be returned.
When a explicit GROUP BY is used, or COUNT ( * ) is used additionally, or there exists an entry in the table, a 1 is returned, which is correct.