await db.insert(employees)
  .values({ employeeId: 123, name: 'John Doe' })
  .onConflictDoUpdate({
    target: employees.employeeId,
    targetWhere: sql`name <> 'John Doe'`,
    set: { name: sql`excluded.name` }
  });
  
await db.insert(employees)
  .values({ employeeId: 123, name: 'John Doe' })
  .onConflictDoUpdate({
    target: employees.employeeId,
    set: { name: 'John Doe' },
    setWhere: sql`name <> 'John Doe'`
  });