Greater / Less Than (> >= < <=)

"Who scored more than 500 runs?" "Which innings were below 50?" These questions need operators that compare size, not just equality. The big thing to get right is the boundary — is 500 itself included or not?

Definition

The relational comparison operators >, >=, < and <= compare two values by their order (numeric size, date order, or alphabetical order for text) and return TRUE, FALSE, or UNKNOWN (if either side is NULL).

• Strict operators (>, <) exclude the boundary value.
• Inclusive operators (>=, <=) include the boundary value.

Syntax

SELECT column_list
FROM table_name
WHERE column_name > value;   -- also >=, <, <=

Example — > 500 (boundary excluded)

SELECT *
FROM players
WHERE runs > 500;

500 itself is not included — Rohit Sharma (exactly 500) is crossed out.

Example — >= 500 (boundary included)

SELECT *
FROM players
WHERE runs >= 500;

>= also keeps the boundary, so Rohit (500) stays.

Example — < 500 and <= 500

SELECT * FROM players WHERE runs < 500;

SELECT * FROM players WHERE runs <= 500;

Notice: > 500 (3 rows) + <= 500 (3 rows) = all 6 players. Opposite operators split the table perfectly — unless NULLs exist, which fall into neither group.

Works on dates and text too

• Dates compare by calendar order: debut < '2010-01-01' = debuted before 2010.
• Text compares alphabetically (using the collation): name > 'M' = names that come after "M" in the dictionary. Careful: 'MS Dhoni' > 'M' is TRUE, because a longer string that starts with "M" sorts after plain "M".

Common mistakes

• ❌ Using > when the question says "at least 500". ✅ "at least" = >=, "more than" = >, "at most" = <=, "less than / below" = <.
• ❌ WHERE runs => 500 → wrong order of symbols. ✅ >= (the = always comes second).
• ❌ WHERE runs > '500' on a number column — works in SQL Server through implicit conversion, but compare numbers with numbers to avoid surprises.
• ❌ Forgetting NULLs: WHERE runs < 50 does not return innings where runs is NULL.

SQL Server extra (rarely used)

SQL Server also accepts !< (not less than, same as >=) and !> (not greater than, same as <=). They are not standard SQL — just recognise them if you see them in old code.

Interview tip

Q: Do WHERE runs > 500 and WHERE NOT runs <= 500 always return the same rows? A: Yes — both drop NULL runs, because NOT UNKNOWN is still UNKNOWN. But WHERE runs > 500 plus WHERE runs <= 500 together do not cover NULL rows.