This is a government financial table so I can't reorder the columns. The first column is an account code, the second column is the name of the account. If I do:
<thead><tr><th scope="col">Account Code</th><th scope="col">Account Name</th></tr></thead>
<tbody><tr><td>12345</td><th scope="row">Fish and Wildlife</th></tr>
...
</tbody>
Will validation barf on that and will screen readers parse it correctly?
In the specifications they do not specify a need for the th to appear as the first column in a table row, and so you should be able to put the th wherever you want.
Table cells may either contain "header" information (see the TH element) or "data" (see the TD element).
<th> just denotes a "header cell", they can exist in <thead>, <tbody> and <tfoot> as appropriate for the content.
You've got your column headers in <thead> and within <th> cells, so the markup you've provided is both schema-correct and in-line with accessibility guidelines. There is nothing wrong with your code.
It's fine. The example in the HTML5 spec is just like that.
Note however, that the <th scope="row"> cell is only a header for those td cells to the right of it, and not for the td cell to the left of it (i.e. the account code).
You could add a headers attribute to each account code td to point to the account name th on the same row, but you'll need to assign a unique id for the account name th on each row.
Ran this document through the w3 validator and it came up clean:
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01//EN"
"http://www.w3.org/TR/html4/strict.dtd">
<html>
<head>
<title>I AM YOUR DOCUMENT TITLE REPLACE ME</title>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<meta http-equiv="Content-Style-Type" content="text/css">
</head>
<body>
<div>
<table>
<thead><tr><th scope="col">Account Code</th><th scope="col">Account Name</th></tr></thead>
<tbody><tr><td>12345</td><th scope="row">Fish and Wildlife</th></tr>
</tbody>
</table>
</div>
</body>
</html>
other than char encoding, which can't be checked because I'm pasting into their document.