[josevalim]

The TDS adapter for MSSQL is almost ready for Ecto v3 thanks to efforts from Milan Jarić. We are also planning to merge it into Ecto SQL, so it doesn't fall behind again.

Meanwhile, I have worked with a company that had to use MSSQL and they ended-up using two Ecto MSSQL adapters at the same time so they could cover all use cases, which is obviously far from ideal.

It is one of these things that, if we had updated it as we went along, it wouldn't have been so much work, but because it fell behind, the amount of work becomes quite big.

However, there are no plans for a built-in sqlite3 adapter, so your observation still holds true. Sometimes you will stumble upon a part of the ecosystem that is not quite there, and then you need to make a decision between waiting, developing it, or using something else.