How Can I Identify Overlapping Date Ranges in MySQL?

Identify overlapping date ranges in MySQL

In MySQL, you can determine whether a specified date range overlaps with a predefined list of date ranges by cleverly applying logic in reverse.

Here is an example:

<code>1983年6月10日至1983年6月14日
1983年7月15日至1983年7月16日
1983年7月18日至1983年7月18日</code>

If we want to check if the date range June 6, 1983 to June 18, 1983 overlaps with any defined range, we can determine the following condition:

Time period not in the list:

• The start time is later than the end time of the comparison period.
• The end time is earlier than the start time of the comparison period.

By excluding time periods that match these criteria, we effectively identify all overlapping time periods.

Border cases:

• The end date is equal to the start date of the comparison period.
• The start date is equal to the end date of the comparison period.

These situations need to be considered individually to determine whether they overlap.

The following SQL query can be used to retrieve overlapping rows based on reverse logic:

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

By using the NOT operator in the WHERE clause, a query that would otherwise find non-overlapping rows is negated, effectively returning overlapping rows.

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