How to query the Stack Exchange API using an OR operator?

Question

I want to query Stack Exchange by title including optional keywords (one of).

How can I query by OR operator?

For example:

/search/advanced?page=1&tagged=java&q=title:http OR class&order=desc&sort=votes&site=stackoverflow

Answer 1

The API currently does not support this, but then neither does the website itself.

The "How do I search?" help page says:

OR operator

To combine results from multiple tags, separate the tag names (enclosed in square brackets) with the word "or": [widgets] or [geegaws] returns questions tagged with either tag.

^{(Emphasis added)}

Note that it only refers to tags in conjunction with the or operator. No facility is made for general or operation.

Here's a related feature request which you can/should upvote.

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Example on the main site:

1. Searching for [winzip] title:folder make gives 3 results (currently).
2. Searching for [winzip] title:folder automate gives 1 result
3. Searching for [winzip] title:folder make or automate gives no results, when it should give at least 3 (fail).
4. [winzip] title:folder (make or automate), etc., also fail.

The API equivalents (one, two, three) give the same results.

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Workarounds:

The Most timely/accurate workaround is: for each of the optional terms, search separately and then combine the results (stripping duplicate matches).

For example:

1. Suppose your keywords were: class and foo.
2. Search for [java] title:http class (only 3303 results, currently).
3. Search for [java] title:http foo (81 results).
4. Repeat for each additional keyword.
5. So we have 3384 gross results, then remove any duplicate question_ids for the final (net) results

This is annoying and inefficient, but it works and is easy to automate.

Other possible workarounds include using a SEDE query, or using a Google search with the site: parameter.