[BUG]: SQLite onConflictDoNothing places the target WHERE after DO NOTHING (partial unique indexes) #6531

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What version of drizzle-orm are you using?

1.0.0-rc.4

What version of drizzle-kit are you using?

N/A

Other packages

Node.js 24 (node:sqlite)

Describe the Bug

onConflictDoNothing({ target, where }) in sqlite-core emits the where clause after do nothing, which SQLite rejects. This makes it impossible to target a partial unique index.

This is the same bug as #1628, which was fixed for Postgres in #2056, but the fix only touched pg-core/query-builders/insert.ts. The SQLite builder still has:

this.config.onConflict.push(sql` on conflict ${targetSql} do nothing${whereSql}`);

Reproduction

import { DatabaseSync } from 'node:sqlite';
import { isNull } from 'drizzle-orm';
import { drizzle } from 'drizzle-orm/node-sqlite';
import { integer, sqliteTable, text } from 'drizzle-orm/sqlite-core';

const users = sqliteTable('users', {
	id: integer().primaryKey(),
	email: text().notNull(),
	deletedAt: integer('deleted_at'),
});

const client = new DatabaseSync(':memory:');
client.exec(`
	CREATE TABLE users (id INTEGER PRIMARY KEY, email TEXT NOT NULL, deleted_at INTEGER);
	CREATE UNIQUE INDEX active_users_email_idx ON users (email) WHERE deleted_at IS NULL;
`);
const db = drizzle({ client });

const query = db
	.insert(users)
	.values({ email: 'a@example.com' })
	.onConflictDoNothing({ target: users.email, where: isNull(users.deletedAt) });

console.log(query.toSQL().sql);
query.run();

Actual

insert into "users" ("id", "email", "deleted_at") values (null, ?, null) on conflict ("users"."email") do nothing where ("users"."deleted_at" is null)

DrizzleQueryError: Failed query: ...
  cause: Error: near "where": syntax error

Expected

insert into "users" ("id", "email", "deleted_at") values (null, ?, null) on conflict ("users"."email") where ("users"."deleted_at" is null) do nothing

Per the [SQLite upsert syntax](https://www.sqlite.org/lang_upsert.html), the conflict target's WHERE must come before DO. Running the expected SQL directly with node:sqlite works as intended.

Workaround

onConflictDoUpdate({ target, targetWhere, set }) already emits the correct order, so a no-op set works in the meantime.

Suggested fix

- this.config.onConflict.push(sql` on conflict ${targetSql} do nothing${whereSql}`);
+ this.config.onConflict.push(sql` on conflict ${targetSql}${whereSql} do nothing`);

Happy to open a PR if that helps.

cc. @hyunbinseo