Fixes for misplaced (identifier) aliases & missing literals

[LeoniePhiline]

The changes are intentionally divided into clean commits (with tests for each).

Thus, the commits are best reviewed individually.

This PR fixes all issues mentioned in #101.

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I added 756ffc2 as a fix for #103.

[LeoniePhiline]

@DerekStride Ready for review.

[matthias-Q]

The changes on cast and count will break the highlighting in nvim-treesitter

[LeoniePhiline]

@matthias-Q I assume they must be adjusted. The nvim queries are quite outdated.

You'll need to adjust https://github.com/nvim-treesitter/nvim-treesitter/blob/master/queries/sql/highlights.scm for nvim, as I do for hx:

In reverse chronological order:

• feat(sql): MariaDB/MySQL syntax, Apache Hive syntax, unified builtin functions, floats, negative integers helix-editor/helix#6041
• feat: Update tree-sitter-sql and migrate highlights.scm to match grammar helix-editor/helix#5772
• Update tree-sitter-sql and improve highlight queries helix-editor/helix#5683

[matthias-Q]

@LeoniePhiline yes, I have a pending PR there: nvim-treesitter/nvim-treesitter#4323

I will add these changes as well. However I would like to have it merged rather sooner than later because I keep adding changes in order to keep up with upstream changes.

@DerekStride can you do another look in that PR in order to get it approved?