matching substring to list of string in django

Question

I have a list of strings (say s = ['1995','1996','1997'] ). I need to find all rows in my database, where some column's first four characters match any item in that list (For example 1995-01-01 or 1996-05-04 ).

Found __in , but it finds exact matches.

Answer 1

import operator
years = ['1995','1996','1997', ...]
query = reduce(operator.or_, [Q(year__startswith=year) for year in years])
results = queryset.filter(query)

This would give you SQL similar to WHERE year LIKE '1995%' OR year LIKE '1996%' ...; which mightn't perform well given your dataset. You might get better performance writing the SQL manually using extra()

Strangely, I just answered another question previously with almost the exact same code!