Unsupported titles redirecting to supported titles and vice-versa

SQL

-- Generated from siteinfo-namespaces in the dump;
-- namespaces.name is the local name, not the canonical name.
with namespaces(id, name) as (
values
    (-2, 'Media'),
    (-1, 'Special'),
    (0, ''),
    (1, 'Talk'),
    (2, 'User'),
    (3, 'User talk'),
    (4, 'Wiktionary'),
    (5, 'Wiktionary talk'),
    (6, 'File'),
    (7, 'File talk'),
    (8, 'MediaWiki'),
    (9, 'MediaWiki talk'),
    (10, 'Template'),
    (11, 'Template talk'),
    (12, 'Help'),
    (13, 'Help talk'),
    (14, 'Category'),
    (15, 'Category talk'),
    (90, 'Thread'),
    (91, 'Thread talk'),
    (92, 'Summary'),
    (93, 'Summary talk'),
    (100, 'Appendix'),
    (101, 'Appendix talk'),
    (102, 'Concordance'),
    (103, 'Concordance talk'),
    (104, 'Index'),
    (105, 'Index talk'),
    (106, 'Rhymes'),
    (107, 'Rhymes talk'),
    (108, 'Transwiki'),
    (109, 'Transwiki talk'),
    (110, 'Thesaurus'),
    (111, 'Thesaurus talk'),
    (114, 'Citations'),
    (115, 'Citations talk'),
    (116, 'Sign gloss'),
    (117, 'Sign gloss talk'),
    (118, 'Reconstruction'),
    (119, 'Reconstruction talk'),
    (828, 'Module'),
    (829, 'Module talk'),
    (2300, 'Gadget'),
    (2301, 'Gadget talk'),
    (2302, 'Gadget definition'),
    (2303, 'Gadget definition talk')
)
select
    replace(concat(
        if(source_namespace.name = '', '', concat(source_namespace.name, ':')),
        page_title
    ), '_', ' ') as source,
    replace(concat(
        if(target_namespace.name = '', '', concat(target_namespace.name, ':')),
        rd_title
    ), '_', ' ') as target
from redirect
join page on page_id = rd_from
join namespaces as target_namespace on target_namespace.id = rd_namespace
join namespaces as source_namespace on source_namespace.id = page_namespace
where (page_namespace = 0 and page_title like "Unsupported_titles/%")
	<> (rd_namespace = 0 and rd_title like "Unsupported_titles/%")
order by source like "Unsupported_titles/%", source;
SQL

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