TrickySQL#337 min readJul 11, 2026
ANY
practice
Practice modeTest yourself instead of reading straight through
Hook: Think of ANY as a crowd test: if even one value in the subquery says yes, the whole condition passes.
Question: What does ANY mean in SQL?
Answer: ANY compares one value against the rows returned by a subquery and returns true if the comparison is true for at least one row. It is a quantified comparison, which means you pair it with operators such as =, >, or <, for example salary > ANY (SELECT ...). A close synonym is SOME.
Interview-Ready Answer: I would say ANY means at least one row from the subquery must make the comparison true. So x = ANY (subquery) is basically the same idea as x IN (subquery), while operators like > ANY let me ask richer questions such as whether a value beats at least one threshold. One important detail is that NULL values can make the result unknown, so I always check the subquery data carefully.
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What ANY really means
ANY is a way to ask, does this value match at least one row from the subquery? That makes it an existential check: you only need one success. In plain English, x > ANY (subquery) means x is bigger than one or more values returned by the subquery.
How the database evaluates it
- The database runs the subquery and gets a set of candidate values.
- For each outer row, it compares the left value to the subquery values using the chosen operator.
- If it finds one true comparison, it can stop and return true for that row.
- If every comparison is false, it returns false.
- If no comparison is true but at least one comparison is unknown because of
NULL, the final result can become unknown, which behaves like false inWHERE. - If the subquery returns no rows,
ANYhas nothing to match, so the result is false.
A useful mental model is this: for clean, non-null data, x > ANY (values) is similar to x > MIN(values), and x < ANY (values) is similar to x < MAX(values). That is only a mental shortcut, not a literal rewrite, because NULL and empty sets change the truth value.
ANY vs IN vs ALL
| Operator | Meaning | Typical use | Empty subquery |
|---|---|---|---|
= ANY | Matches at least one row | Same idea as IN | false |
IN | Matches one listed value | Simple equality filter | false |
> ANY | Greater than at least one row | Beat one threshold | false |
ALL | Matches every row | Stricter filtering | true |
= ANY and IN are the same idea for subqueries, but ANY is more flexible because it works with other operators. That is why interviewers like this topic: it looks tiny, but it tests whether you understand set logic, three-valued logic, and the difference between a row-by-row comparison and a simple list check.
When and why to use it
Use ANY when you want a condition that succeeds if one or more rows match. It is common in pricing, ranking, and eligibility checks, such as price > ANY or department = ANY. If you only need equality, many teams prefer IN because it is shorter and easier to scan, but ANY is the right tool when the operator is not equality.
Performance and under-the-hood notes
Most mature databases do not literally compare every row forever. They often rewrite simple ANY predicates into a semi-join, which is a join that only checks whether a match exists. That means the engine may stop early once it finds one good row. With 10,000 outer rows and 100,000 inner rows, a naive nested loop could do up to 1 billion comparisons, but a hash semi-join or indexed lookup can cut that work drastically.
Two practical details matter in interviews: duplicates usually do not change the answer, because one match is enough; and correlated subqueries can be slower because the inner query may run once per outer row unless the optimizer transforms it. That is why indexes on the subquery columns help, especially for large tables.
Edge cases to remember
NULLvalues can make the result unknown, so filter them out when they are not meaningful.- An empty subquery makes
ANYfalse, not true. SOMEis a synonym ofANYin standard SQL.NOT INis not the same topic asANY; it has its ownNULLtraps, so be careful when translating logic.
Real-World Story: In an e-commerce checkout service, a team used ANY to show products whose price was cheaper than at least one competitor price from a live feed. One day, a new region had no competitor rows yet, and the filter became empty because price < ANY (empty set) is false. Customers saw a blank category page, logs showed filtered_products=0 and competitor_rows=0, and conversions dipped until the team added a fallback path for empty feeds.
The lesson is simple: ANY is powerful, but it is still logic over real data. If the subquery can be empty or contain NULL, you need to decide whether that should mean no match, a default value, or a separate branch in the query.
SQL
DROP TABLE IF EXISTS employees;
DROP TABLE IF EXISTS salary_benchmarks;
DROP TABLE IF EXISTS active_departments;
-- Small sample data that lets us see the operator clearly.
-- PostgreSQL syntax is used here because it supports ANY with subqueries directly.
CREATE TEMP TABLE employees (
employee_id INT PRIMARY KEY,
employee_name TEXT NOT NULL,
department TEXT NOT NULL,
salary INT NOT NULL
);
CREATE TEMP TABLE salary_benchmarks (
benchmark_id INT PRIMARY KEY,
amount INT
);
CREATE TEMP TABLE active_departments (
department TEXT PRIMARY KEY
);
INSERT INTO employees (employee_id, employee_name, department, salary) VALUES
(1, 'Ava', 'Engineering', 120000),
(2, 'Ben', 'Engineering', 90000),
(3, 'Mia', 'Sales', 70000),
(4, 'Noah', 'Support', 50000);
INSERT INTO salary_benchmarks (benchmark_id, amount) VALUES
(1, 80000),
(2, 100000),
(3, NULL);
INSERT INTO active_departments (department) VALUES
('Engineering'),
('Sales');
-- 1) ANY means: the comparison must be true for at least one subquery row.
-- Here we keep only employees whose salary is greater than at least one benchmark.
SELECT employee_name, salary
FROM employees
WHERE salary > ANY (
SELECT amount
FROM salary_benchmarks
WHERE amount IS NOT NULL
)
ORDER BY employee_name;
-- 2) = ANY is the same idea as IN when comparing to a subquery.
-- This returns employees in one of the active departments.
SELECT employee_name, department
FROM employees
WHERE department = ANY (
SELECT department
FROM active_departments
)
ORDER BY employee_name;
-- 3) Edge case: empty subquery.
-- There is no row to satisfy the comparison, so ANY is false.
SELECT
CASE
WHEN 75000 > ANY (
SELECT amount
FROM salary_benchmarks
WHERE 1 = 0
)
THEN 'matched'
ELSE 'no match'
END AS empty_set_result;
-- 4) Edge case: subquery returns only NULL.
-- Every comparison becomes unknown, so the WHERE condition does not pass.
SELECT
CASE
WHEN 75000 > ANY (
SELECT amount
FROM salary_benchmarks
WHERE amount IS NULL
)
THEN 'matched'
ELSE 'not matched because the result is unknown'
END AS null_only_result;Follow-up & Tricky Questions:
- What is the difference between
ANYandALL?ANYneeds one true comparison;ALLneeds every comparison to be true. If the subquery is empty,ANYis false andALLis true, which is a classic interview trap. - Is
x = ANY (subquery)the same asx IN (subquery)? Yes, for the usual subquery case they express the same membership test. The difference is thatANYcan also use other operators like>or<. - What happens if the subquery returns
NULL? ANULLcan make the result unknown if no comparison is true. In aWHEREclause, unknown behaves like false, so the row is filtered out. - Can duplicates in the subquery change the result? Usually no, because one matching row is enough. Duplicates may still affect performance, but not the truth value of the predicate.
- How would you optimize a slow
ANYquery? Check indexes on the subquery columns, see whether the optimizer can use a semi-join, and remove unnecessary correlation. Often the biggest win is making the subquery sargable, meaning the database can use an index efficiently. - Tricky: Is
NOT (x = ANY (...))the same asx <> ALL (...)? In standard SQL logic, that is the right equivalence to think about, butNULLcan still make both sides unknown. So do not skip the null check just because the expressions look logically neat. - Tricky: Is
x > ANY (...)the same asx > MIN(...)? Only as a rough intuition when the subquery is non-empty and contains no meaningfulNULLvalues. The real predicate is row-based, so empty sets and unknowns can change the answer. - Tricky: Does an empty subquery mean the condition passes because there is nothing to compare? No. For
ANY, no matching row means false. This is one of the easiest mistakes to make under interview pressure.
Common Mistakes:
- Confusing
ANYwithALL. Correction:ANYneeds one win;ALLneeds every row to win. - Thinking
= ANYis different fromIN. Correction: for subqueries, they express the same membership idea. - Ignoring
NULLrows. Correction: filter out meaningless nulls or decide how unknown should behave. - Forgetting empty-set behavior. Correction: an empty subquery makes
ANYfalse, so add a fallback if that is not what you want.
Memory Hook: ANY = one yes in the crowd. If even one person raises a hand, the answer is yes.
Cheat Sheet:
x = ANY (subquery)is the subquery version of membership.ANYworks with comparison operators, not just equality.- One true comparison is enough.
- Empty subquery = false for
ANY. NULLcan make the result unknown.SOMEis a synonym forANY.
Practice Tasks:
- Write a query that finds orders with a total greater than
ANYof the totals in a table of recent orders. - Rewrite a simple
INquery as= ANYand confirm the results are the same. - Add one
NULLrow to the subquery and observe how the result changes.