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    <ul> <li>First, let's exhaustively examine what an "overlap" means and optimize your boolean expression.</li> </ul> <hr> <p>An overlap is any of the following conditions:</p> <pre> Start1 End1 --------------------------------------------------------------------------------- Start2 End2 Start2 End2 Start2 End2 </pre> <p>And is NOT any of the following conditions:</p> <pre> Start1 End1 --------------------------------------------------------------------------------- Start2 End2 Start2 End2 </pre> <p>If you look carefully, you'll notice <code>Start2 &lt; End1 AND End2 &gt; Start1</code> defines this relationship, so you can reduce your expression to this.</p> <hr> <ul> <li><p>Second, you can put this in a <code>WHERE</code> condition for your cursor instead of looping through every row and checking.</p></li> <li><p>Third, since you're just checking whether something exists or not, you can use an <code>IF EXISTS</code> clause instead of looping through a cursor and checking.</p></li> <li><p>Finally, you can condense this all down to a single query using an <code>INNER JOIN</code> on itself or <code>WHERE EXISTS</code>, depending on how you want your final output to look. To get all the overlaps in the table, you can try something like the following (the <code>t2.id &gt; t1.id</code> is to only get each overlap once):</p> <pre><code>SELECT t1.id, t2.id FROM MyTable t1 INNER JOIN MyTable t2 ON t2.id &gt; t1.id AND t2.start &lt; t1.end AND t2.end &gt; t1.start </code></pre></li> </ul>
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    1. POHow to check dates don't overlap in a table using TSQL
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    1. CO@ShaneCourtrille Thanks for the edit, but the condition you added was already there (see the second line).
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    2. COI added the 2nd line where the new date range contains the original date range. You had two lines both of which were when at least one part of the new date range was inside the the original date range. In the original 2nd line for instance Start 2 was inside Start1/End1.
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    3. CO@ShaneCourtrille No, actually you added a fourth line which was exactly the same as my second line. What you see now is rolled back to exactly how it was before your edit...(check the revision history) Either way though we agree this version is ok?
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