[Solved] Why does the condition start1 = start2 correctly detect overlap between two date ranges? — Ans: Because it ensures the first range starts before the second ends and ends after... | SQL

SQL - Advanced Query Patterns

Why does the condition start1 <= end2 AND end1 >= start2 correctly detect overlap between two date ranges?

ABecause it checks if the ranges are exactly the same

BBecause it only checks if the first range is inside the second

CBecause it ensures the first range starts before the second ends and ends after the second starts

DBecause it ignores the start dates and only compares end dates

Step-by-Step Solution

Solution:

Step 1: Analyze the condition parts
start1 <= end2 means the first range starts before or when the second ends; end1 >= start2 means the first range ends after or when the second starts.
Step 2: Understand how this ensures overlap
Both conditions together guarantee the ranges share at least one date, so they overlap.
Final Answer:
Because it ensures the first range starts before the second ends and ends after the second starts -> Option C
Quick Check:
Overlap condition logic = Because it ensures the first range starts before the second ends and ends after the second starts [OK]

Quick Trick: Overlap means first starts before second ends and ends after second starts [OK]

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Why does the condition start1 = start2 correctly detect overlap between two date ranges?