What MySQL Output is
Not a file format at all. It is what the MySQL command line prints when you run a query: a box drawn with plus signs, dashes and pipes, with a line underneath saying how many rows were in the set.
Anyone who has run a query in a terminal and wants the answer in a spreadsheet.
What Markdown is
A Markdown table is rows of pipe-separated cells with a dashed rule under the header. Alignment is set by placing colons in that rule.
README files, GitHub issues, documentation sites, Obsidian and Notion.
What changes when you convert MySQL Output to Markdown
The rules and the trailing row count are dropped and the pipes become column boundaries. MySQL prints an unset value as the four characters NULL, which arrives here as an empty cell, because that is what NULL means and because a literal string of NULL in a spreadsheet is worse than a blank. Paste it as CSV instead and every row becomes one column full of pipes, which is why this is its own format.
Cells are padded so the source lines up in a plain text editor, pipes inside values are escaped, and line breaks inside a cell become <br> because a Markdown table row cannot span lines.
What carries over from MySQL Output to Markdown
MySQL records 3 things about a table that Markdown has no way to hold.
MySQL distinguishes a number from the text of a number; Markdown does not, so every value arrives as text and has to be re-parsed by whatever reads it next.
An empty cell and a missing one are the same thing in Markdown, so a null and an empty string in the MySQL both come out blank and can no longer be told apart.
A line break inside a cell ends the row in Markdown, so line breaks are replaced rather than carried through.
The identifier 007 comes out of the Markdown as 007. Reading it as a number would have made it 7, and an id that changes value is worse than one that stays text.
The role "Analyst, data" survives with its comma, in one cell rather than split across two. That is the first thing to check in any converted table, and the usual place a Markdown file goes wrong.
The quotes around Jonah "Jo" Pryce are left as a plain quote character in the Markdown.