[petrzjunior]

JetBrains's IntelliJ and friends do that with language plugins. They detect the language according to keywords and patterns and are able to do highlighting and intellisense for multiple languages in a single file. I have not tried this with LSP though, because LSP support landed just in the last version.

[ComputerGuru]

Yeah, (neo)vim can do that for non-lsp with a filetype like html.css or similar whichbloads both syntax rules possibly with customizations to determine when it switches into which of the two modes. But again, I don’t know how that works with lsp.

[scns]

In Intellij you can connect to the DB and get autocomplete in SQL strings.