Do a generic T-SQL LIKE query on post HTML content and format the results nicely.
Wildcards that work include % for any string, _ for any character, [ABCDE] or [A-E] for a letter from A to E, and [^ABCDE] or [^A-E] for any character *except* A to E. To match a literal "%", "_", "[" or "]", insert a backslash ("\") before it. Remember to wrap the search pattern in % signs if you don't want to anchor it to the beginning and/or end of the post, and remember that the content being searched is parsed HTML, *not* Markdown.
This query will probably time out on SO unless you narrow down the date range! Try e.g. limiting the search to posts made within one or two years. On smaller sites, you can leave in the default values.
Q&A for programmers
-- PostHTML: HTML code to search for (T-SQL LIKE pattern, \ escapes)
-- ExcludeHTML: HTML code to exclude (T-SQL LIKE pattern, \ escapes)
-- StartDate: Earliest posting date (YYYY-MM-DD)
-- EndDate: Latest posting date (YYYY-MM-DD)
-- MaxResults: Maximum number of result rows
with Matched as (
select * from Posts
where Body like ##PostHTML:string?%search%## escape char(92)
and Body not like ##ExcludeHTML:string?<nothing>## escape char(92)
select top ##MaxResults:int?100##
Post.Id as [Post Link],
PostTypes.Name as [Type],
when Author.Id is null then Post.OwnerDisplayName
else 'site://users/' + cast(Author.Id as varchar) + '|' + Author.DisplayName
end as [Author],
coalesce(Post.ViewCount, Parent.ViewCount) as [Views],
coalesce(Post.Tags, Parent.Tags) as [Tags]
from Matched as Post
join PostTypes on Post.PostTypeId = PostTypes.Id
left join Posts as Parent on Post.ParentId = Parent.Id
left join Users as Author on Post.OwnerUserId = Author.Id
where Post.CreationDate between ##StartDate:string?2000-01-01## and ##EndDate:string?2999-12-31## + ' 23:59:59'