Q.What will happen if in the above query we write “Aaliya” as “AALIYA” or “aaliya” or “AaLIYA”? Will the query generate the same output or an error?
[Context: the query referred to is Example 9.5 — mysql> SELECT * FROM EMPLOYEE WHERE NOT Ename = 'Aaliya';]

Case Sensitivity: A First Look

Imagine you're writing your name on a form. You might write "Rahul" with a capital R, or "rahul" all in lowercase. To you, both mean the same person. But to a computer, those two spellings are as different as "Rahul" and "Sharma" — they are treated as entirely separate things.

That is the core idea of case sensitivity: the distinction between uppercase (capital) and lowercase letters. A system that is case-sensitive treats 'A' and 'a' as different characters. A system that is case-insensitive treats them as the same.

The Everyday Intuition

In human language, we use capital letters for specific purposes — the start of a sentence, proper names, titles. But we rarely confuse meaning because of them. "Apple" (the fruit) and "apple" (the same fruit) are obviously the same word to us. The capital letter is just a convention, not a change in identity.

Computers, however, are literal machines. They don't "understand" meaning the way we do. They compare things character by character. The letter 'A' has a different internal code than 'a'. So when a computer checks if "Apple" equals "apple", it sees two different sequences and says: no match.

Where It Matters

Case sensitivity shows up in many places you will encounter as a commerce or humanities student:

• Email addresses: Most email systems are case-insensitive. [PII:email] reaches the same inbox as [PII:email]. But the part before the @ might be treated differently by some systems — so it's safest to use all lowercase.
• Passwords: These are almost always case-sensitive. Password123 and password123 are completely different passwords. This is why you must type your password exactly as you created it, with the same capitals.
• File names: On some systems (like Windows), file names are case-insensitive — Report.docx and report.docx refer to the same file. On others (like Linux), they are case-sensitive — those would be two different files.
• Website URLs: The domain name part (like google.com) is case-insensitive. But everything after the first slash can be case-sensitive, depending on the server. So Example.com/Page might work, but example.com/page might not. …