SQL · Theory

last()

Theory

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last()

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: last(): create two demo rows, then SELECT qty >= 2 ordered. Say which labels come back.

Exam tip

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

last() — sample query

-- last()
CREATE TABLE demo (
  id INTEGER PRIMARY KEY,
  label TEXT NOT NULL,
  qty INTEGER DEFAULT 0
);
INSERT INTO demo (id, label, qty) VALUES
  (1, 'alpha', 2),
  (2, 'beta', 5);
SELECT label, qty FROM demo WHERE qty >= 2 ORDER BY qty DESC;

last(): create two demo rows, then SELECT qty >= 2 ordered. Say which labels come back.

Short notes

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

-- last() CREATE TABLE demo ( id INTEGER PRIMARY KEY, label TEXT NOT NULL, qty INTEGER DEFAULT 0 ); INSERT INTO demo (id, label, qty) VALUES (1, 'alpha', 2), (2, 'beta', 5); SELECT label, qty FROM demo WHERE qty >= 2 ORDER BY qty DESC;

last()

last() — sample query

Short notes

Questions

last()

last() — sample query

Short notes

Questions