Warmer Than Yesterday

MediumSQLSQL

Solve this the way you would in the interview: out loud, on a timer, with an AI interviewer asking follow-ups while you code. You get a scored report at the end.

Practice this as a mock interviewFree to start, no account needed

Problem

Table readings: day TEXT a date as 'YYYY-MM-DD', unique temp INTEGER Return every day that was warmer than the calendar day before it. Columns, in this order: day, temp. Order by day, ascending. Days can be missing. A day counts only if the row for the previous calendar day exists and is colder.

Examples

Input: readings day | temp 2026-03-01 | 10 2026-03-02 | 14 2026-03-04 | 20
Output: 2026-03-02 | 14
March 4 has no reading for March 3 to compare against.

Constraints

  • The first day in the table never qualifies.

What the interviewer grades

A correct solution is one of five scores. The report also grades problem understanding (did you clarify inputs and edge cases before coding), problem solving, communication while you work, code quality, and testing. See a sample report, or read up on the pattern in the lessons.

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