diff --git a/src/lib/gtfs/agencies.ts b/src/lib/gtfs/agencies.ts
index f92f75a9..69ff5528 100644
--- a/src/lib/gtfs/agencies.ts
+++ b/src/lib/gtfs/agencies.ts
@@ -1,8 +1,8 @@
-import {
+import type {
   Agency,
   QueryOptions,
   SqlOrderBy,
-  SqlSelect,
+  QueryResult,
   SqlWhere,
 } from '../../types/global_interfaces.ts';
 import { openDb } from '../db.ts';
@@ -15,9 +15,9 @@ import {
 /*
  * Returns an array of all agencies that match the query parameters.
  */
-export function getAgencies(
+export function getAgencies<Fields extends keyof Agency>(
   query: SqlWhere = {},
-  fields: SqlSelect = [],
+  fields: Fields[] = [],
   orderBy: SqlOrderBy = [],
   options: QueryOptions = {},
 ) {
@@ -31,5 +31,5 @@ export function getAgencies(
     .prepare(
       `${selectClause} FROM ${tableName} ${whereClause} ${orderByClause};`,
     )
-    .all() as Agency[];
+    .all() as QueryResult<Agency, Fields>[];
 }
diff --git a/src/lib/gtfs/areas.ts b/src/lib/gtfs/areas.ts
index e03ce6dd..f728c056 100644
--- a/src/lib/gtfs/areas.ts
+++ b/src/lib/gtfs/areas.ts
@@ -1,8 +1,8 @@
-import {
+import type {
   Area,
   QueryOptions,
   SqlOrderBy,
-  SqlSelect,
+  QueryResult,
   SqlWhere,
 } from '../../types/global_interfaces.ts';
 import { openDb } from '../db.ts';
@@ -15,9 +15,9 @@ import {
 /*
  * Returns an array of all areas that match the query parameters.
  */
-export function getAreas(
+export function getAreas<Fields extends keyof Area>(
   query: SqlWhere = {},
-  fields: SqlSelect = [],
+  fields: Fields[] = [],
   orderBy: SqlOrderBy = [],
   options: QueryOptions = {},
 ) {
@@ -31,5 +31,5 @@ export function getAreas(
     .prepare(
       `${selectClause} FROM ${tableName} ${whereClause} ${orderByClause};`,
     )
-    .all() as Area[];
+    .all() as QueryResult<Area, Fields>[];
 }
diff --git a/src/lib/gtfs/attributions.ts b/src/lib/gtfs/attributions.ts
index 90b846ba..6d34d035 100644
--- a/src/lib/gtfs/attributions.ts
+++ b/src/lib/gtfs/attributions.ts
@@ -1,8 +1,8 @@
-import {
+import type {
   Attribution,
   QueryOptions,
   SqlOrderBy,
-  SqlSelect,
+  QueryResult,
   SqlWhere,
 } from '../../types/global_interfaces.ts';
 import { openDb } from '../db.ts';
@@ -15,9 +15,9 @@ import {
 /*
  * Returns an array of all attributions that match the query parameters.
  */
-export function getAttributions(
+export function getAttributions<Fields extends keyof Attribution>(
   query: SqlWhere = {},
-  fields: SqlSelect = [],
+  fields: Fields[] = [],
   orderBy: SqlOrderBy = [],
   options: QueryOptions = {},
 ) {
@@ -31,5 +31,5 @@ export function getAttributions(
     .prepare(
       `${selectClause} FROM ${tableName} ${whereClause} ${orderByClause};`,
     )
-    .all() as Attribution[];
+    .all() as QueryResult<Attribution, Fields>[];
 }
diff --git a/src/lib/gtfs/booking-rules.ts b/src/lib/gtfs/booking-rules.ts
index 96f9025e..d4c79f0a 100644
--- a/src/lib/gtfs/booking-rules.ts
+++ b/src/lib/gtfs/booking-rules.ts
@@ -1,8 +1,8 @@
-import {
+import type {
   BookingRule,
   QueryOptions,
   SqlOrderBy,
-  SqlSelect,
+  QueryResult,
   SqlWhere,
 } from '../../types/global_interfaces.ts';
 import { openDb } from '../db.ts';
@@ -15,9 +15,9 @@ import {
 /*
  * Returns an array of all booking rules that match the query parameters.
  */
-export function getBookingRules(
+export function getBookingRules<Fields extends keyof BookingRule>(
   query: SqlWhere = {},
-  fields: SqlSelect = [],
+  fields: Fields[] = [],
   orderBy: SqlOrderBy = [],
   options: QueryOptions = {},
 ) {
@@ -31,5 +31,5 @@ export function getBookingRules(
     .prepare(
       `${selectClause} FROM ${tableName} ${whereClause} ${orderByClause};`,
     )
-    .all() as BookingRule[];
+    .all() as QueryResult<BookingRule, Fields>[];
 }
diff --git a/src/lib/gtfs/calendar-dates.ts b/src/lib/gtfs/calendar-dates.ts
index b7d7298e..c8fb3f5f 100644
--- a/src/lib/gtfs/calendar-dates.ts
+++ b/src/lib/gtfs/calendar-dates.ts
@@ -1,8 +1,8 @@
-import {
+import type {
   CalendarDate,
   QueryOptions,
   SqlOrderBy,
-  SqlSelect,
+  QueryResult,
   SqlWhere,
 } from '../../types/global_interfaces.ts';
 import { openDb } from '../db.ts';
@@ -15,9 +15,9 @@ import {
 /*
  * Returns an array of calendarDates that match the query parameters.
  */
-export function getCalendarDates(
+export function getCalendarDates<Fields extends keyof CalendarDate>(
   query: SqlWhere = {},
-  fields: SqlSelect = [],
+  fields: Fields[] = [],
   orderBy: SqlOrderBy = [],
   options: QueryOptions = {},
 ) {
@@ -31,5 +31,5 @@ export function getCalendarDates(
     .prepare(
       `${selectClause} FROM ${tableName} ${whereClause} ${orderByClause};`,
     )
-    .all() as CalendarDate[];
+    .all() as QueryResult<CalendarDate, Fields>[];
 }
diff --git a/src/lib/gtfs/calendars.ts b/src/lib/gtfs/calendars.ts
index b443e34d..827eb5b7 100644
--- a/src/lib/gtfs/calendars.ts
+++ b/src/lib/gtfs/calendars.ts
@@ -1,8 +1,8 @@
-import {
+import type {
   Calendar,
   QueryOptions,
   SqlOrderBy,
-  SqlSelect,
+  QueryResult,
   SqlWhere,
 } from '../../types/global_interfaces.ts';
 import { openDb } from '../db.ts';
@@ -16,9 +16,9 @@ import {
 /*
  * Returns an array of calendars that match the query parameters.
  */
-export function getCalendars(
+export function getCalendars<Fields extends keyof Calendar>(
   query: SqlWhere = {},
-  fields: SqlSelect = [],
+  fields: Fields[] = [],
   orderBy: SqlOrderBy = [],
   options: QueryOptions = {},
 ) {
@@ -32,7 +32,7 @@ export function getCalendars(
     .prepare(
       `${selectClause} FROM ${tableName} ${whereClause} ${orderByClause};`,
     )
-    .all() as Calendar[];
+    .all() as QueryResult<Calendar, Fields>[];
 }
 
 /*
diff --git a/src/lib/gtfs/fare-attributes.ts b/src/lib/gtfs/fare-attributes.ts
index a2e7de99..f2a5f111 100644
--- a/src/lib/gtfs/fare-attributes.ts
+++ b/src/lib/gtfs/fare-attributes.ts
@@ -1,8 +1,8 @@
-import {
+import type {
   FareAttribute,
   QueryOptions,
   SqlOrderBy,
-  SqlSelect,
+  QueryResult,
   SqlWhere,
 } from '../../types/global_interfaces.ts';
 import { openDb } from '../db.ts';
@@ -15,9 +15,9 @@ import {
 /*
  * Returns an array of all fare attributes that match the query parameters.
  */
-export function getFareAttributes(
+export function getFareAttributes<Fields extends keyof FareAttribute>(
   query: SqlWhere = {},
-  fields: SqlSelect = [],
+  fields: Fields[] = [],
   orderBy: SqlOrderBy = [],
   options: QueryOptions = {},
 ) {
@@ -31,5 +31,5 @@ export function getFareAttributes(
     .prepare(
       `${selectClause} FROM ${tableName} ${whereClause} ${orderByClause};`,
     )
-    .all() as FareAttribute[];
+    .all() as QueryResult<FareAttribute, Fields>[];
 }
diff --git a/src/lib/gtfs/fare-leg-rules.ts b/src/lib/gtfs/fare-leg-rules.ts
index e3a09f85..cd7d9e7f 100644
--- a/src/lib/gtfs/fare-leg-rules.ts
+++ b/src/lib/gtfs/fare-leg-rules.ts
@@ -1,8 +1,8 @@
-import {
+import type {
   FareLegRule,
   QueryOptions,
   SqlOrderBy,
-  SqlSelect,
+  QueryResult,
   SqlWhere,
 } from '../../types/global_interfaces.ts';
 import { openDb } from '../db.ts';
@@ -15,9 +15,9 @@ import {
 /*
  * Returns an array of all fare leg rules that match the query parameters.
  */
-export function getFareLegRules(
+export function getFareLegRules<Fields extends keyof FareLegRule>(
   query: SqlWhere = {},
-  fields: SqlSelect = [],
+  fields: Fields[] = [],
   orderBy: SqlOrderBy = [],
   options: QueryOptions = {},
 ) {
@@ -31,5 +31,5 @@ export function getFareLegRules(
     .prepare(
       `${selectClause} FROM ${tableName} ${whereClause} ${orderByClause};`,
     )
-    .all() as FareLegRule[];
+    .all() as QueryResult<FareLegRule, Fields>[];
 }
diff --git a/src/lib/gtfs/fare-media.ts b/src/lib/gtfs/fare-media.ts
index 7f3fc46c..c2d3d955 100644
--- a/src/lib/gtfs/fare-media.ts
+++ b/src/lib/gtfs/fare-media.ts
@@ -1,8 +1,8 @@
-import {
+import type {
   FareMedia,
   QueryOptions,
   SqlOrderBy,
-  SqlSelect,
+  QueryResult,
   SqlWhere,
 } from '../../types/global_interfaces.ts';
 import { openDb } from '../db.ts';
@@ -15,9 +15,9 @@ import {
 /*
  * Returns an array of all fare media that match the query parameters.
  */
-export function getFareMedia(
+export function getFareMedia<Fields extends keyof FareMedia>(
   query: SqlWhere = {},
-  fields: SqlSelect = [],
+  fields: Fields[] = [],
   orderBy: SqlOrderBy = [],
   options: QueryOptions = {},
 ) {
@@ -31,5 +31,5 @@ export function getFareMedia(
     .prepare(
       `${selectClause} FROM ${tableName} ${whereClause} ${orderByClause};`,
     )
-    .all() as FareMedia[];
+    .all() as QueryResult<FareMedia, Fields>[];
 }
diff --git a/src/lib/gtfs/fare-products.ts b/src/lib/gtfs/fare-products.ts
index f3f7a5db..77dd82d1 100644
--- a/src/lib/gtfs/fare-products.ts
+++ b/src/lib/gtfs/fare-products.ts
@@ -1,8 +1,8 @@
-import {
+import type {
   FareProduct,
   QueryOptions,
   SqlOrderBy,
-  SqlSelect,
+  QueryResult,
   SqlWhere,
 } from '../../types/global_interfaces.ts';
 import { openDb } from '../db.ts';
@@ -15,9 +15,9 @@ import {
 /*
  * Returns an array of all fare products that match the query parameters.
  */
-export function getFareProducts(
+export function getFareProducts<Fields extends keyof FareProduct>(
   query: SqlWhere = {},
-  fields: SqlSelect = [],
+  fields: Fields[] = [],
   orderBy: SqlOrderBy = [],
   options: QueryOptions = {},
 ) {
@@ -31,5 +31,5 @@ export function getFareProducts(
     .prepare(
       `${selectClause} FROM ${tableName} ${whereClause} ${orderByClause};`,
     )
-    .all() as FareProduct[];
+    .all() as QueryResult<FareProduct, Fields>[];
 }
diff --git a/src/lib/gtfs/fare-rules.ts b/src/lib/gtfs/fare-rules.ts
index e709c9d1..6a3baeb8 100644
--- a/src/lib/gtfs/fare-rules.ts
+++ b/src/lib/gtfs/fare-rules.ts
@@ -1,8 +1,8 @@
-import {
+import type {
   FareRule,
   QueryOptions,
   SqlOrderBy,
-  SqlSelect,
+  QueryResult,
   SqlWhere,
 } from '../../types/global_interfaces.ts';
 import { openDb } from '../db.ts';
@@ -15,9 +15,9 @@ import {
 /*
  * Returns an array of all fare rules that match the query parameters.
  */
-export function getFareRules(
+export function getFareRules<Fields extends keyof FareRule>(
   query: SqlWhere = {},
-  fields: SqlSelect = [],
+  fields: Fields[] = [],
   orderBy: SqlOrderBy = [],
   options: QueryOptions = {},
 ) {
@@ -31,5 +31,5 @@ export function getFareRules(
     .prepare(
       `${selectClause} FROM ${tableName} ${whereClause} ${orderByClause};`,
     )
-    .all() as FareRule[];
+    .all() as QueryResult<FareRule, Fields>[];
 }
diff --git a/src/lib/gtfs/fare-transfer-rules.ts b/src/lib/gtfs/fare-transfer-rules.ts
index 9564357f..8fd97b0f 100644
--- a/src/lib/gtfs/fare-transfer-rules.ts
+++ b/src/lib/gtfs/fare-transfer-rules.ts
@@ -1,8 +1,8 @@
-import {
+import type {
   FareTransferRule,
   QueryOptions,
   SqlOrderBy,
-  SqlSelect,
+  QueryResult,
   SqlWhere,
 } from '../../types/global_interfaces.ts';
 import { openDb } from '../db.ts';
@@ -15,9 +15,9 @@ import {
 /*
  * Returns an array of all fare transfer rules that match the query parameters.
  */
-export function getFareTransferRules(
+export function getFareTransferRules<Fields extends keyof FareTransferRule>(
   query: SqlWhere = {},
-  fields: SqlSelect = [],
+  fields: Fields[] = [],
   orderBy: SqlOrderBy = [],
   options: QueryOptions = {},
 ) {
@@ -31,5 +31,5 @@ export function getFareTransferRules(
     .prepare(
       `${selectClause} FROM ${tableName} ${whereClause} ${orderByClause};`,
     )
-    .all() as FareTransferRule[];
+    .all() as QueryResult<FareTransferRule, Fields>[];
 }
diff --git a/src/lib/gtfs/feed-info.ts b/src/lib/gtfs/feed-info.ts
index 68ae439c..137f346c 100644
--- a/src/lib/gtfs/feed-info.ts
+++ b/src/lib/gtfs/feed-info.ts
@@ -1,8 +1,8 @@
-import {
+import type {
   FeedInfo,
   QueryOptions,
   SqlOrderBy,
-  SqlSelect,
+  QueryResult,
   SqlWhere,
 } from '../../types/global_interfaces.ts';
 import { openDb } from '../db.ts';
@@ -15,9 +15,9 @@ import {
 /*
  * Returns an array of all feed info that match the query parameters.
  */
-export function getFeedInfo(
+export function getFeedInfo<Fields extends keyof FeedInfo>(
   query: SqlWhere = {},
-  fields: SqlSelect = [],
+  fields: Fields[] = [],
   orderBy: SqlOrderBy = [],
   options: QueryOptions = {},
 ) {
@@ -31,5 +31,5 @@ export function getFeedInfo(
     .prepare(
       `${selectClause} FROM ${tableName} ${whereClause} ${orderByClause};`,
     )
-    .all() as FeedInfo[];
+    .all() as QueryResult<FeedInfo, Fields>[];
 }
diff --git a/src/lib/gtfs/frequencies.ts b/src/lib/gtfs/frequencies.ts
index 024225f8..d276521a 100644
--- a/src/lib/gtfs/frequencies.ts
+++ b/src/lib/gtfs/frequencies.ts
@@ -1,8 +1,8 @@
-import {
+import type {
   Frequency,
   QueryOptions,
   SqlOrderBy,
-  SqlSelect,
+  QueryResult,
   SqlWhere,
 } from '../../types/global_interfaces.ts';
 import { openDb } from '../db.ts';
@@ -15,9 +15,9 @@ import {
 /*
  * Returns an array of all frequencies that match the query parameters.
  */
-export function getFrequencies(
+export function getFrequencies<Fields extends keyof Frequency>(
   query: SqlWhere = {},
-  fields: SqlSelect = [],
+  fields: Fields[] = [],
   orderBy: SqlOrderBy = [],
   options: QueryOptions = {},
 ) {
@@ -31,5 +31,5 @@ export function getFrequencies(
     .prepare(
       `${selectClause} FROM ${tableName} ${whereClause} ${orderByClause};`,
     )
-    .all() as Frequency[];
+    .all() as QueryResult<Frequency, Fields>[];
 }
diff --git a/src/lib/gtfs/levels.ts b/src/lib/gtfs/levels.ts
index b316884e..e9fd1bcb 100644
--- a/src/lib/gtfs/levels.ts
+++ b/src/lib/gtfs/levels.ts
@@ -1,8 +1,8 @@
-import {
+import type {
   Level,
   QueryOptions,
   SqlOrderBy,
-  SqlSelect,
+  QueryResult,
   SqlWhere,
 } from '../../types/global_interfaces.ts';
 import { openDb } from '../db.ts';
@@ -15,9 +15,9 @@ import {
 /*
  * Returns an array of all levels that match the query parameters.
  */
-export function getLevels(
+export function getLevels<Fields extends keyof Level>(
   query: SqlWhere = {},
-  fields: SqlSelect = [],
+  fields: Fields[] = [],
   orderBy: SqlOrderBy = [],
   options: QueryOptions = {},
 ) {
@@ -31,5 +31,5 @@ export function getLevels(
     .prepare(
       `${selectClause} FROM ${tableName} ${whereClause} ${orderByClause};`,
     )
-    .all() as Level[];
+    .all() as QueryResult<Level, Fields>[];
 }
diff --git a/src/lib/gtfs/location-group-stops.ts b/src/lib/gtfs/location-group-stops.ts
index 8d503629..2d244944 100644
--- a/src/lib/gtfs/location-group-stops.ts
+++ b/src/lib/gtfs/location-group-stops.ts
@@ -1,8 +1,8 @@
-import {
+import type {
   LocationGroupStop,
   QueryOptions,
   SqlOrderBy,
-  SqlSelect,
+  QueryResult,
   SqlWhere,
 } from '../../types/global_interfaces.ts';
 import { openDb } from '../db.ts';
@@ -15,9 +15,9 @@ import {
 /*
  * Returns an array of all location group stops that match the query parameters.
  */
-export function getLocationGroupStops(
+export function getLocationGroupStops<Fields extends keyof LocationGroupStop>(
   query: SqlWhere = {},
-  fields: SqlSelect = [],
+  fields: Fields[] = [],
   orderBy: SqlOrderBy = [],
   options: QueryOptions = {},
 ) {
@@ -31,5 +31,5 @@ export function getLocationGroupStops(
     .prepare(
       `${selectClause} FROM ${tableName} ${whereClause} ${orderByClause};`,
     )
-    .all() as LocationGroupStop[];
+    .all() as QueryResult<LocationGroupStop, Fields>[];
 }
diff --git a/src/lib/gtfs/location-groups.ts b/src/lib/gtfs/location-groups.ts
index b9206589..fdcd209d 100644
--- a/src/lib/gtfs/location-groups.ts
+++ b/src/lib/gtfs/location-groups.ts
@@ -1,8 +1,8 @@
-import {
+import type {
   LocationGroup,
   QueryOptions,
   SqlOrderBy,
-  SqlSelect,
+  QueryResult,
   SqlWhere,
 } from '../../types/global_interfaces.ts';
 import { openDb } from '../db.ts';
@@ -15,9 +15,9 @@ import {
 /*
  * Returns an array of all location groups that match the query parameters.
  */
-export function getLocationGroups(
+export function getLocationGroups<Fields extends keyof LocationGroup>(
   query: SqlWhere = {},
-  fields: SqlSelect = [],
+  fields: Fields[] = [],
   orderBy: SqlOrderBy = [],
   options: QueryOptions = {},
 ) {
@@ -31,5 +31,5 @@ export function getLocationGroups(
     .prepare(
       `${selectClause} FROM ${tableName} ${whereClause} ${orderByClause};`,
     )
-    .all() as LocationGroup[];
+    .all() as QueryResult<LocationGroup, Fields>[];
 }
diff --git a/src/lib/gtfs/locations.ts b/src/lib/gtfs/locations.ts
index ff57ee23..1c70b1d7 100644
--- a/src/lib/gtfs/locations.ts
+++ b/src/lib/gtfs/locations.ts
@@ -1,8 +1,8 @@
-import {
+import type {
   Location,
   QueryOptions,
   SqlOrderBy,
-  SqlSelect,
+  QueryResult,
   SqlWhere,
 } from '../../types/global_interfaces.ts';
 import { openDb } from '../db.ts';
@@ -15,9 +15,9 @@ import {
 /*
  * Returns an array of all locations that match the query parameters.
  */
-export function getLocations(
+export function getLocations<Fields extends keyof Location>(
   query: SqlWhere = {},
-  fields: SqlSelect = [],
+  fields: Fields[] = [],
   orderBy: SqlOrderBy = [],
   options: QueryOptions = {},
 ) {
@@ -31,5 +31,5 @@ export function getLocations(
     .prepare(
       `${selectClause} FROM ${tableName} ${whereClause} ${orderByClause};`,
     )
-    .all() as Location[];
+    .all() as QueryResult<Location, Fields>[];
 }
diff --git a/src/lib/gtfs/networks.ts b/src/lib/gtfs/networks.ts
index 2d657199..d5188772 100644
--- a/src/lib/gtfs/networks.ts
+++ b/src/lib/gtfs/networks.ts
@@ -1,8 +1,8 @@
-import {
+import type {
   Network,
   QueryOptions,
   SqlOrderBy,
-  SqlSelect,
+  QueryResult,
   SqlWhere,
 } from '../../types/global_interfaces.ts';
 import { openDb } from '../db.ts';
@@ -15,9 +15,9 @@ import {
 /*
  * Returns an array of all networks that match the query parameters.
  */
-export function getNetworks(
+export function getNetworks<Fields extends keyof Network>(
   query: SqlWhere = {},
-  fields: SqlSelect = [],
+  fields: Fields[] = [],
   orderBy: SqlOrderBy = [],
   options: QueryOptions = {},
 ) {
@@ -31,5 +31,5 @@ export function getNetworks(
     .prepare(
       `${selectClause} FROM ${tableName} ${whereClause} ${orderByClause};`,
     )
-    .all() as Network[];
+    .all() as QueryResult<Network, Fields>[];
 }
diff --git a/src/lib/gtfs/pathways.ts b/src/lib/gtfs/pathways.ts
index c9952858..03343231 100644
--- a/src/lib/gtfs/pathways.ts
+++ b/src/lib/gtfs/pathways.ts
@@ -1,8 +1,8 @@
-import {
+import type {
   Pathway,
   QueryOptions,
   SqlOrderBy,
-  SqlSelect,
+  QueryResult,
   SqlWhere,
 } from '../../types/global_interfaces.ts';
 import { openDb } from '../db.ts';
@@ -15,9 +15,9 @@ import {
 /*
  * Returns an array of all pathways that match the query parameters.
  */
-export function getPathways(
+export function getPathways<Fields extends keyof Pathway>(
   query: SqlWhere = {},
-  fields: SqlSelect = [],
+  fields: Fields[] = [],
   orderBy: SqlOrderBy = [],
   options: QueryOptions = {},
 ) {
@@ -31,5 +31,5 @@ export function getPathways(
     .prepare(
       `${selectClause} FROM ${tableName} ${whereClause} ${orderByClause};`,
     )
-    .all() as Pathway[];
+    .all() as QueryResult<Pathway, Fields>[];
 }
diff --git a/src/lib/gtfs/route-networks.ts b/src/lib/gtfs/route-networks.ts
index 603c0f27..524c6c88 100644
--- a/src/lib/gtfs/route-networks.ts
+++ b/src/lib/gtfs/route-networks.ts
@@ -1,8 +1,8 @@
-import {
+import type {
   QueryOptions,
   RouteNetwork,
   SqlOrderBy,
-  SqlSelect,
+  QueryResult,
   SqlWhere,
 } from '../../types/global_interfaces.ts';
 import { openDb } from '../db.ts';
@@ -15,9 +15,9 @@ import {
 /*
  * Returns an array of all route_networks that match the query parameters.
  */
-export function getRouteNetworks(
+export function getRouteNetworks<Fields extends keyof RouteNetwork>(
   query: SqlWhere = {},
-  fields: SqlSelect = [],
+  fields: Fields[] = [],
   orderBy: SqlOrderBy = [],
   options: QueryOptions = {},
 ) {
@@ -31,5 +31,5 @@ export function getRouteNetworks(
     .prepare(
       `${selectClause} FROM ${tableName} ${whereClause} ${orderByClause};`,
     )
-    .all() as RouteNetwork[];
+    .all() as QueryResult<RouteNetwork, Fields>[];
 }
diff --git a/src/lib/gtfs/routes.ts b/src/lib/gtfs/routes.ts
index f805470b..b1f73e8c 100644
--- a/src/lib/gtfs/routes.ts
+++ b/src/lib/gtfs/routes.ts
@@ -1,10 +1,10 @@
 import { omit, pick } from 'lodash-es';
 
-import {
+import type {
   QueryOptions,
   Route,
   SqlOrderBy,
-  SqlSelect,
+  QueryResult,
   SqlWhere,
 } from '../../types/global_interfaces.ts';
 import { openDb } from '../db.ts';
@@ -46,9 +46,9 @@ function buildTripSubquery(query: { service_id?: string; stop_id?: string }) {
  * A `service_id` query parameter may be passed to limit routes to specific
  * calendars.
  */
-export function getRoutes(
+export function getRoutes<Fields extends keyof Route>(
   query: SqlWhere = {},
-  fields: SqlSelect = [],
+  fields: Fields[] = [],
   orderBy: SqlOrderBy = [],
   options: QueryOptions = {},
 ) {
@@ -80,5 +80,5 @@ export function getRoutes(
     .prepare(
       `${selectClause} FROM ${tableName} ${whereClause} ${orderByClause};`,
     )
-    .all() as Route[];
+    .all() as QueryResult<Route, Fields>[];
 }
diff --git a/src/lib/gtfs/shapes.ts b/src/lib/gtfs/shapes.ts
index 93b4dc40..4b859bda 100644
--- a/src/lib/gtfs/shapes.ts
+++ b/src/lib/gtfs/shapes.ts
@@ -2,11 +2,11 @@ import { compact, omit, pick } from 'lodash-es';
 import { FeatureCollection } from 'geojson';
 import { featureCollection } from '@turf/helpers';
 
-import {
+import type {
   QueryOptions,
   Shape,
   SqlOrderBy,
-  SqlSelect,
+  QueryResult,
   SqlWhere,
 } from '../../types/global_interfaces.ts';
 import { openDb } from '../db.ts';
@@ -32,9 +32,9 @@ function buildTripSubquery(query: { [key: string]: string }) {
  * parameter may be passed to find all shapes for a trip. A `direction_id`
  * query parameter may be passed to find all shapes for a direction.
  */
-export function getShapes(
+export function getShapes<Fields extends keyof Shape>(
   query: SqlWhere = {},
-  fields: SqlSelect = [],
+  fields: Fields[] = [],
   orderBy: SqlOrderBy = [],
   options: QueryOptions = {},
 ) {
@@ -73,7 +73,7 @@ export function getShapes(
     .prepare(
       `${selectClause} FROM ${tableName} ${whereClause} ${orderByClause};`,
     )
-    .all() as Shape[];
+    .all() as QueryResult<Shape, Fields>[];
 }
 
 /*
diff --git a/src/lib/gtfs/stop-areas.ts b/src/lib/gtfs/stop-areas.ts
index 7dd6f7ea..cd3cc2b8 100644
--- a/src/lib/gtfs/stop-areas.ts
+++ b/src/lib/gtfs/stop-areas.ts
@@ -1,7 +1,7 @@
-import {
+import type {
   QueryOptions,
   SqlOrderBy,
-  SqlSelect,
+  QueryResult,
   SqlWhere,
   StopArea,
 } from '../../types/global_interfaces.ts';
@@ -15,9 +15,9 @@ import {
 /*
  * Returns an array of all stop areas that match the query parameters.
  */
-export function getStopAreas(
+export function getStopAreas<Fields extends keyof StopArea>(
   query: SqlWhere = {},
-  fields: SqlSelect = [],
+  fields: Fields[] = [],
   orderBy: SqlOrderBy = [],
   options: QueryOptions = {},
 ) {
@@ -31,5 +31,5 @@ export function getStopAreas(
     .prepare(
       `${selectClause} FROM ${tableName} ${whereClause} ${orderByClause};`,
     )
-    .all() as StopArea[];
+    .all() as QueryResult<StopArea, Fields>[];
 }
diff --git a/src/lib/gtfs/stop-times.ts b/src/lib/gtfs/stop-times.ts
index fe8e1fe4..d748a63d 100644
--- a/src/lib/gtfs/stop-times.ts
+++ b/src/lib/gtfs/stop-times.ts
@@ -1,9 +1,9 @@
 import { omit } from 'lodash-es';
 import sqlString from 'sqlstring-sqlite';
-import {
+import type {
   QueryOptions,
   SqlOrderBy,
-  SqlSelect,
+  QueryResult,
   SqlWhere,
   StopTime,
 } from '../../types/global_interfaces.ts';
@@ -19,9 +19,9 @@ import { getServiceIdsByDate } from './calendars.ts';
 /*
  * Returns an array of stoptimes that match the query parameters.
  */
-export function getStoptimes(
+export function getStoptimes<Fields extends keyof StopTime>(
   query: SqlWhere = {},
-  fields: SqlSelect = [],
+  fields: Fields[] = [],
   orderBy: SqlOrderBy = [],
   options: QueryOptions = {},
 ) {
@@ -79,5 +79,5 @@ export function getStoptimes(
     .prepare(
       `${selectClause} FROM ${tableName} ${whereClause} ${orderByClause};`,
     )
-    .all() as StopTime[];
+    .all() as QueryResult<StopTime, Fields>[];
 }
diff --git a/src/lib/gtfs/stops.ts b/src/lib/gtfs/stops.ts
index 9d6cc3a8..ce0ec929 100644
--- a/src/lib/gtfs/stops.ts
+++ b/src/lib/gtfs/stops.ts
@@ -1,10 +1,10 @@
 import { omit, orderBy, pick } from 'lodash-es';
 import { FeatureCollection } from 'geojson';
 
-import {
+import type {
   QueryOptions,
   SqlOrderBy,
-  SqlSelect,
+  QueryResult,
   SqlWhere,
   Stop,
 } from '../../types/global_interfaces.ts';
@@ -38,9 +38,9 @@ function buildStoptimeSubquery(query: { [key: string]: string }) {
  * `direction_id` query parameter may be passed to find all shapes for a
  * direction.
  */
-export function getStops(
+export function getStops<Fields extends keyof Stop>(
   query: SqlWhere = {},
-  fields: SqlSelect = [],
+  fields: Fields[] = [],
   orderBy: SqlOrderBy = [],
   options: QueryOptions = {},
 ) {
@@ -109,7 +109,7 @@ export function getStops(
     .prepare(
       `${selectClause} FROM ${tableName} ${whereClause} ${orderByClause};`,
     )
-    .all() as Stop[];
+    .all() as QueryResult<Stop, Fields>[];
 }
 
 /*
diff --git a/src/lib/gtfs/timeframes.ts b/src/lib/gtfs/timeframes.ts
index 87c11968..fe406fdf 100644
--- a/src/lib/gtfs/timeframes.ts
+++ b/src/lib/gtfs/timeframes.ts
@@ -1,7 +1,7 @@
-import {
+import type {
   QueryOptions,
   SqlOrderBy,
-  SqlSelect,
+  QueryResult,
   SqlWhere,
   Timeframe,
 } from '../../types/global_interfaces.ts';
@@ -15,9 +15,9 @@ import {
 /*
  * Returns an array of all timeframes that match the query parameters.
  */
-export function getTimeframes(
+export function getTimeframes<Fields extends keyof Timeframe>(
   query: SqlWhere = {},
-  fields: SqlSelect = [],
+  fields: Fields[] = [],
   orderBy: SqlOrderBy = [],
   options: QueryOptions = {},
 ) {
@@ -31,5 +31,5 @@ export function getTimeframes(
     .prepare(
       `${selectClause} FROM ${tableName} ${whereClause} ${orderByClause};`,
     )
-    .all() as Timeframe[];
+    .all() as QueryResult<Timeframe, Fields>[];
 }
diff --git a/src/lib/gtfs/transfers.ts b/src/lib/gtfs/transfers.ts
index 0811b1f6..fabe1380 100644
--- a/src/lib/gtfs/transfers.ts
+++ b/src/lib/gtfs/transfers.ts
@@ -1,7 +1,7 @@
-import {
+import type {
   QueryOptions,
   SqlOrderBy,
-  SqlSelect,
+  QueryResult,
   SqlWhere,
   Transfer,
 } from '../../types/global_interfaces.ts';
@@ -15,9 +15,9 @@ import {
 /*
  * Returns an array of all transfers that match the query parameters.
  */
-export function getTransfers(
+export function getTransfers<Fields extends keyof Transfer>(
   query: SqlWhere = {},
-  fields: SqlSelect = [],
+  fields: Fields[] = [],
   orderBy: SqlOrderBy = [],
   options: QueryOptions = {},
 ) {
@@ -31,5 +31,5 @@ export function getTransfers(
     .prepare(
       `${selectClause} FROM ${tableName} ${whereClause} ${orderByClause};`,
     )
-    .all() as Transfer[];
+    .all() as QueryResult<Transfer, Fields>[];
 }
diff --git a/src/lib/gtfs/translations.ts b/src/lib/gtfs/translations.ts
index a55a984b..316cacac 100644
--- a/src/lib/gtfs/translations.ts
+++ b/src/lib/gtfs/translations.ts
@@ -1,7 +1,7 @@
-import {
+import type {
   QueryOptions,
   SqlOrderBy,
-  SqlSelect,
+  QueryResult,
   SqlWhere,
   Translation,
 } from '../../types/global_interfaces.ts';
@@ -15,9 +15,9 @@ import {
 /*
  * Returns an array of all translations that match the query parameters.
  */
-export function getTranslations(
+export function getTranslations<Fields extends keyof Translation>(
   query: SqlWhere = {},
-  fields: SqlSelect = [],
+  fields: Fields[] = [],
   orderBy: SqlOrderBy = [],
   options: QueryOptions = {},
 ) {
@@ -31,5 +31,5 @@ export function getTranslations(
     .prepare(
       `${selectClause} FROM ${tableName} ${whereClause} ${orderByClause};`,
     )
-    .all() as Translation[];
+    .all() as QueryResult<Translation, Fields>[];
 }
diff --git a/src/lib/gtfs/trips.ts b/src/lib/gtfs/trips.ts
index f89a3973..75328c4e 100644
--- a/src/lib/gtfs/trips.ts
+++ b/src/lib/gtfs/trips.ts
@@ -1,7 +1,7 @@
-import {
+import type {
   QueryOptions,
   SqlOrderBy,
-  SqlSelect,
+  QueryResult,
   SqlWhere,
   Trip,
 } from '../../types/global_interfaces.ts';
@@ -15,9 +15,9 @@ import {
 /*
  * Returns an array of all trips that match the query parameters.
  */
-export function getTrips(
+export function getTrips<Fields extends keyof Trip>(
   query: SqlWhere = {},
-  fields: SqlSelect = [],
+  fields: Fields[] = [],
   orderBy: SqlOrderBy = [],
   options: QueryOptions = {},
 ) {
@@ -31,5 +31,5 @@ export function getTrips(
     .prepare(
       `${selectClause} FROM ${tableName} ${whereClause} ${orderByClause};`,
     )
-    .all() as Trip[];
+    .all() as QueryResult<Trip, Fields>[];
 }
diff --git a/src/types/global_interfaces.ts b/src/types/global_interfaces.ts
index 49ae448b..ef21535b 100644
--- a/src/types/global_interfaces.ts
+++ b/src/types/global_interfaces.ts
@@ -76,6 +76,12 @@ export type SqlWhere = Record<string, null | SqlValue | SqlValue[]>;
 
 export type SqlSelect = string[];
 
+export type QueryResult<Base extends object, Select extends keyof Base> = [
+  Select,
+] extends [never]
+  ? Base
+  : Pick<Base, Select>;
+
 export type SqlOrderBy = Array<[string, 'ASC' | 'DESC']>;
 
 export interface QueryOptions {