How to Efficiently Identify Overlapping Date Ranges in MySQL?

MySQL date range comparison algorithm

In MySQL, we often need to determine whether a given date range overlaps with any date range in the stored list. To solve this problem, let us consider the relationship between two date ranges:

• Completely Contains: One range falls completely within another range.
• Start or end overlap: A range shares a boundary with another range.
• Non-overlapping: There are no shared boundaries, one range ends before the other starts.

Identify overlapping ranges

The key is to find those ranges that do not overlap. By defining this condition negatively, we can narrow the focus to the following criteria:

• The start time is later than the end time of the target range.
• The end time is earlier than the start time of the target range.

In SQL, the result of converting this logic into query form is as follows:

<code class="language-sql">SELECT *
FROM periods
WHERE NOT (range_start > @check_period_end OR range_end < @check_period_start)</code>

By reversing the logic, we can retrieve overlapping ranges as follows:

<code class="language-sql">SELECT *
FROM periods
WHERE range_start <= @check_period_end AND range_end >= @check_period_start</code>

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