Question

I have a column in my table which contains the values 0 or 1.
Now I want to select the start of the last period of 1’s.

Imagine I’ve the next table with 2 columns. The last period of 1’s are the ID’s 4 and 3.
The start of this period is ID = 3.

ID – VALUE

• 5 – 0
• 4 – 1 <– last period
• 3 – 1 <– last period
• 2 – 0
• 1 – 1 <– period longer ago
• 0 – 0

But how do I select this record with one query (and maybe a bit of PHP) and without select all records?

Edit:

Using MySQL

Answer 1

You can try finding highest id with value 1 for which closest lower id has value 0.
In sql this would be:

SELECT p1.id FROM periods p1
WHERE p1.value = 1
AND ( SELECT p2.value FROM periods p2 
      WHERE p2.id<p1.id 
      ORDER BY p2.id DESC LIMIT 1 ) = 0
ORDER BY p1.id DESC LIMIT 1