Q: How to convert json array into csv?
A: Use jq like this:
jq -r '(
    # Print CSV header
    (first | keys_unsorted) as $keys |
    $keys,
    # Print values for each object
    map([.[$keys[]]])[]
  ) | @csv'

Q: How to filter csv by some condition?
A: Use csvkit/csvsql:
pipx install csvkit
csvsql --query "SELECT * FROM file WHERE age <= 47" file.csv