SQLite - WHERE Clause & UDFs

Question

Intro

I have the following SQLite table with 198,305 geocoded portuguese postal codes:

CREATE TABLE "pt_postal" (
  "code" text NOT N         


        

Answer 1

This also return 873 records, ordered by distance in ~0.04 seconds:

SELECT
    "code",
    geo(38.73311, -9.138707, "geo_latitude", "geo_longitude") AS "distance"
    FROM "pt_postal" WHERE 1 = 1
        AND "geo_latitude" BETWEEN 38.7241268076 AND 38.7420931924
        AND "geo_longitude" BETWEEN -9.15022289523 AND -9.12719110477
    GROUP BY "code"
        HAVING "distance" <= 1
    ORDER BY "distance" ASC
LIMIT 2048;

The reason this page doesn't have a GROUP BY clause is MySQL specific:

A HAVING clause can refer to any column or alias named in a select_expr in the SELECT list or in outer subqueries, and to aggregate functions. However, the SQL standard requires that HAVING must reference only columns in the GROUP BY clause or columns used in aggregate functions. To accommodate both standard SQL and the MySQL-specific behavior of being able to refer columns in the SELECT list, MySQL 5.0.2 and up permit HAVING to refer to columns in the SELECT list, columns in the GROUP BY clause, columns in outer subqueries, and to aggregate functions.

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If no primary / unique key is available, the following hack also works (albeit a bit slower - ~0.16 seconds):

SELECT
    "code",
    geo(38.73311, -9.138707, "geo_latitude", "geo_longitude") AS "distance"
    FROM "pt_postal" WHERE 1 = 1
        AND "geo_latitude" BETWEEN 38.7241268076 AND 38.7420931924
        AND "geo_longitude" BETWEEN -9.15022289523 AND -9.12719110477
    GROUP BY _ROWID_
        HAVING "distance" <= 1
    ORDER BY "distance" ASC
LIMIT 2048;