Uncle Bob is against SQL in programing languages

It is worse than that. The relational algebra is a line encoding. Just as raw bits cannot be stored on magnetic media or transmitted over a wire as they are found, but only after undergoing translation in order to adapt to the physical properties of the medium, so raw data requires extensive transformation, less in order to be stored than in order to be retrieved. The relational algebra is one of the great works of the human mind, but it is analogous to a Layer-1 protocol. The great mistake has been to try to force it upwards into Layers 5, 6, 7, and 7++, rather than find appropriate information-architectural analogues for those layers. Even Martin seems to say that it is Layer 6. The problem is much deeper than that.