SQL · Theory

max()

Theory

122/439

max()

MAX(marks) highest value. Topper query: ORDER BY marks DESC LIMIT 1 or WHERE marks = (SELECT MAX(marks) FROM students). The subquery form keeps ties.

LIMIT 1 hides ties. Say that in the interview.

Trap — MAX without mentioning ties.

On the example next to this theory — max() — aggregate functions collapse many rows into one summary row.

Exam tip

MAX(marks). Ties: WHERE marks = (SELECT MAX(marks) FROM students).

max() — sample query

CREATE TABLE scores (id INTEGER PRIMARY KEY, marks INTEGER);
INSERT INTO scores VALUES (1, 80), (2, 90), (3, 70);
SELECT COUNT(*) AS n, AVG(marks) AS avg_marks, MAX(marks) AS top
FROM scores;

max() — aggregate functions collapse many rows into one summary row.

Short notes

DefMAX = largest non-NULL value.
RuleSubquery keeps ties. LIMIT 1 may hide them.
TrapAssuming one unique topper.

SQL · Theory

max()

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Theory

122/439

max()

MAX(marks) highest value. Topper query: ORDER BY marks DESC LIMIT 1 or WHERE marks = (SELECT MAX(marks) FROM students). The subquery form keeps ties.

LIMIT 1 hides ties. Say that in the interview.

Trap — MAX without mentioning ties.

On the example next to this theory — max() — aggregate functions collapse many rows into one summary row.

Exam tip

MAX(marks). Ties: WHERE marks = (SELECT MAX(marks) FROM students).

max() — sample query

CREATE TABLE scores (id INTEGER PRIMARY KEY, marks INTEGER);
INSERT INTO scores VALUES (1, 80), (2, 90), (3, 70);
SELECT COUNT(*) AS n, AVG(marks) AS avg_marks, MAX(marks) AS top
FROM scores;

max() — aggregate functions collapse many rows into one summary row.

Short notes

DefMAX = largest non-NULL value.
RuleSubquery keeps ties. LIMIT 1 may hide them.
TrapAssuming one unique topper.

max()

max() — sample query

Short notes

Questions

max()

max() — sample query

Short notes

Questions