MySQL

Install the MySQL driver

For Drizzle, the standard driver is mysql2.

pnpm --filter @workspace/db add mysql2
pnpm --filter @workspace/db remove postgres

Update environment variables

The project already validates DATABASE_URL, so the main change is using a MySQL connection string instead of a PostgreSQL one.

DATABASE_URL="mysql://root:password@127.0.0.1:3306/turbostarter"

If you run a managed MySQL provider, use that provider's connection string instead.

Replace the database client

The current database package uses postgres-js. Replace it with a mysql2 connection or pool in packages/db/src/server.ts.

import { drizzle } from "drizzle-orm/mysql2";
import mysql from "mysql2/promise";

import { env } from "./env";
import * as schema from "./schema";

const client = mysql.createPool(env.DATABASE_URL);

export const db = drizzle({
  client,
  schema,
  casing: "snake_case",
});

The rest of the package structure can stay the same.

Switch Drizzle Kit to MySQL

Update packages/db/drizzle.config.ts to use the Drizzle Kit MySQL dialect:

import { defineConfig } from "drizzle-kit";

import { env } from "./src/env";

export default defineConfig({
  out: "./migrations",
  schema: "./src/schema/index.ts",
  dialect: "mysql",
  casing: "snake_case",
  dbCredentials: {
    url: env.DATABASE_URL,
  },
});

Update Better Auth

The auth package is PostgreSQL-first today. In packages/auth/src/server.ts, switch the Better Auth Drizzle adapter provider to MySQL:

database: drizzleAdapter(db, {
  provider: "mysql",
  schema,
}),

Better Auth's Drizzle adapter supports MySQL directly, so this part is straightforward.

Convert the schema to MySQL

The schema files currently use drizzle-orm/pg-core in:

• packages/db/src/schema/auth.ts
• packages/db/src/schema/billing.ts

Move those files to drizzle-orm/mysql-core and replace the PostgreSQL-only schema helpers.

The most common replacements are:

• pgTable -> mysqlTable
• pgEnum(...) -> mysqlEnum(...)
• PostgreSQL timestamp definitions -> MySQL datetime(...) or timestamp(...) equivalents
• PostgreSQL-specific helper imports -> MySQL or dialect-neutral types

For example, the billing enums in packages/db/src/schema/billing.ts should become MySQL enums instead of PostgreSQL enums:

import { mysqlEnum, mysqlTable, text } from "drizzle-orm/mysql-core";

export const subscriptionStatusEnum = mysqlEnum("subscription_status", [
  "active",
  "canceled",
  "incomplete",
  "incomplete_expired",
  "past_due",
  "paused",
  "trialing",
  "unpaid",
]);

packages/db/src/utils/index.ts also needs attention. Right now it imports PgTable and PgTableWithColumns, and its buildConflictUpdateColumns helper emits raw SQL using the PostgreSQL/SQLite excluded.column_name pattern.

That helper is not directly reusable for MySQL upserts.

Update upserts and returning queries

This is the biggest MySQL-specific difference in the current setup.

The current codebase uses PostgreSQL-style upserts with .onConflictDoUpdate(...) and frequently calls .returning() after inserts and updates. MySQL does not follow the same pattern.

In practice, you need to review files such as:

• packages/billing/shared/src/server/customer.ts
• packages/billing/shared/src/server/subscription.ts
• packages/billing/shared/src/server/order.ts
• packages/auth/src/scripts/seed.ts

The usual query changes are:

• .onConflictDoUpdate(...) -> .onDuplicateKeyUpdate(...)
• .returning() after inserts -> $returningId() only when you need inserted primary keys, or a follow-up select
• .returning() after updates -> a follow-up select if you need the updated row data back

For example, this current PostgreSQL-style upsert:

return db
  .insert(customer)
  .values(data)
  .onConflictDoUpdate({
    target: [customer.externalId, customer.provider],
    set: data,
  })
  .returning();

needs to be reworked for MySQL around onDuplicateKeyUpdate, without relying on PostgreSQL conflict targets or returning().

Regenerate migrations from scratch

Once the schema, utilities, and query layer are updated, generate a fresh MySQL migration set.

The existing migration history in packages/db/migrations was generated for PostgreSQL, so don't reuse it as-is for MySQL.

rm -rf packages/db/migrations
pnpm with-env turbo db:generate
pnpm with-env pnpm --filter @workspace/db db:migrate

After that, you can keep using the same Drizzle workflows:

• pnpm with-env turbo db:generate
• pnpm with-env pnpm --filter @workspace/db db:migrate
• pnpm with-env pnpm --filter @workspace/db db:studio