diff --git a/lib/relational.js b/lib/relational.js
index e5b9f2ce..443420de 100644
--- a/lib/relational.js
+++ b/lib/relational.js
@@ -42,7 +42,7 @@ if (process.env.NODE_ENV !== 'production') {
 export { prisma };
 
 export function getDateQuery(field, unit, timezone) {
-  const db = getDatabase(process.env.DATABASE_URL);
+  const db = getDatabase(process.env.DATABASE_URL, process.env.DATABASE_TYPE);
 
   if (db === POSTGRESQL) {
     if (timezone) {
@@ -63,7 +63,7 @@ export function getDateQuery(field, unit, timezone) {
 }
 
 export function getTimestampInterval(field) {
-  const db = getDatabase(process.env.DATABASE_URL);
+  const db = getDatabase(process.env.DATABASE_URL, process.env.DATABASE_TYPE);
 
   if (db === POSTGRESQL) {
     return `floor(extract(epoch from max(${field}) - min(${field})))`;
@@ -164,7 +164,7 @@ export async function runQuery(query) {
 }
 
 export async function rawQuery(query, params = []) {
-  const db = getDatabase(process.env.DATABASE_URL);
+  const db = getDatabase(process.env.DATABASE_URL, process.env.DATABASE_TYPE);
 
   if (db !== POSTGRESQL && db !== MYSQL) {
     return Promise.reject(new Error('Unknown database.'));