fix(mysql, singlestore): scope migration table lookup to current database

[Shay12tg]

Problem

When running Drizzle migrations against multiple databases on the same MySQL
server, migrate() fails on any database that doesn't already have the
__drizzle_migrations table — even though Drizzle is supposed to create it
automatically.

The upgradeIfNeeded function checks information_schema.tables for the
migrations table, but doesn't filter by table_schema. This means it finds
the table in a different database, concludes the current database isn't new,
skips CREATE TABLE, and then fails when it tries to read from a table that
doesn't exist in the current database.

Postgres, CockroachDB, and MSSQL don't have this problem because they already
filter by migrationsSchema. MySQL and SingleStore were missing the equivalent
filter.

Fix

Add WHERE table_schema = DATABASE() to both information_schema queries in
the MySQL and SingleStore upgradeIfNeeded functions. DATABASE() returns the
currently selected database name — the MySQL equivalent of Postgres's schema
scoping.

2 files changed, 4 lines added:

• drizzle-orm/src/up-migrations/mysql.ts
• drizzle-orm/src/up-migrations/singlestore.ts

[Copilot]

Pull request overview

Fixes MySQL/SingleStore migration bootstrapping when multiple databases exist on the same server by ensuring __drizzle_migrations existence/shape checks are scoped to the currently selected database.

Changes:

• Scope information_schema.tables lookup with WHERE table_schema = DATABASE() in MySQL/SingleStore upgradeIfNeeded().
• Scope information_schema.columns lookup with WHERE table_schema = DATABASE() in MySQL/SingleStore upgradeIfNeeded().

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated no comments.

File	Description
drizzle-orm/src/up-migrations/mysql.ts	Restricts migration table existence/column queries to the active MySQL database via DATABASE().
drizzle-orm/src/up-migrations/singlestore.ts	Applies the same current-database scoping for SingleStore’s information_schema checks.

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