Antipattern: Sort Data Randomly
Understand the issues caused by sorting data randomly in SQL queries, including poor performance due to costly table scans. Learn why this common technique does not scale well and explore better approaches for selecting random rows efficiently.
We'll cover the following...
We'll cover the following...
The most common SQL trick to pick a random row from a query is to sort the query randomly and pick the first row. This technique is easy to understand and easy to implement:
Although this is a popular solution, it quickly shows its weakness. To understand this weakness, let’s first compare it to conventional sorting, in which we compare values in a column and order the rows according to the size of the value in that column. This ...