BETWEEN clause versus <= AND >=

Question

Is there a performance difference between using a BETWEEN clause or using <= AND >= comparisons?

i.e. these two queries:

SELECT *  
  FROM table           


        

Answer 1

Actually it depends on your DBMS engine.

Some database management systems will compute twice your expression (once for each comparison), and only once when you use BETWEEN.

Actually if the expression can have a non-deterministic result BETWEEN will have a different behaviour, compare the following in SQLite:

WHERE RANDOM() BETWEEN x AND y -- one random value generated

WHERE RANDOM() >= x AND RANDOM() <= y -- two distinct random values generated

This can be very time consuming if your expression is (for example) a subquery.