This Leetcode problem Report Contiguous Dates LeetCode Solution is done in SQL.

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Report Contiguous Dates LeetCode Solution

Problem Statement

Primary key for this table is fail_date.
Failed table contains the days of failed tasks.

Primary key for this table is success_date.
Succeeded table contains the days of succeeded tasks.

A system is running one task every day. Every task is independent of the previous tasks. The tasks can fail or succeed.

Write an SQL query to generate a report of period_state for each continuous interval of days in the period from 2019-01-01 to 2019-12-31.

period_state is ‘failed’ if tasks in this interval failed or ‘succeeded’ if tasks in this interval succeeded. Interval of days are retrieved as start_date and end_date.
Order result by start_date.

The result format is in the following example.

Example 1:
Input:

Output:

Explanation:
The report ignored the system state in 2018 as we care about the system in the period 2019-01-01 to 2019-12-31.
From 2019-01-01 to 2019-01-03 all tasks succeeded and the system state was “succeeded”.
From 2019-01-04 to 2019-01-05 all tasks failed and system state was “failed”.
From 2019-01-06 to 2019-01-06 all tasks succeeded and system state was “succeeded”.

Report Contiguous Dates LeetCode Solution MySQL

select 
  period_state, 
  start_date, 
  end_date 
from 
  (
    select 
      'failed' as period_state, 
      f1.fail_date as start_date, 
      f2.fail_date as end_date 
    from 
      (
        select 
          fail_date 
        from 
          Failed 
        where 
          fail_date between '2019-01-01' 
          and '2019-12-31' 
          and date_sub(fail_date, interval 1 day) not in (
            select 
              * 
            from 
              Failed 
            where 
              fail_date between '2019-01-01' 
              and '2019-12-31'
          )
      ) as f1, 
      (
        select 
          fail_date 
        from 
          Failed 
        where 
          fail_date between '2019-01-01' 
          and '2019-12-31' 
          and date_add(fail_date, interval 1 day) not in (
            select 
              * 
            from 
              Failed 
            where 
              fail_date between '2019-01-01' 
              and '2019-12-31'
          )
      ) as f2 
    where 
      f1.fail_date <= f2.fail_date 
    group by 
      f1.fail_date 
    union 
    select 
      'succeeded' as period_state, 
      s1.success_date as start_date, 
      s2.success_date as end_date 
    from 
      (
        select 
          success_date 
        from 
          Succeeded 
        where 
          success_date between '2019-01-01' 
          and '2019-12-31' 
          and date_sub(success_date, interval 1 day) not in (
            select 
              * 
            from 
              Succeeded 
            where 
              success_date between '2019-01-01' 
              and '2019-12-31'
          )
      ) as s1, 
      (
        select 
          success_date 
        from 
          Succeeded 
        where 
          success_date between '2019-01-01' 
          and '2019-12-31' 
          and date_add(success_date, interval 1 day) not in (
            select 
              * 
            from 
              Succeeded 
            where 
              success_date between '2019-01-01' 
              and '2019-12-31'
          )
      ) as s2 
    where 
      s1.success_date <= s2.success_date 
    group by 
      s1.success_date
  ) as p 
order by 
  start_date;Code language: SQL (Structured Query Language) (sql)