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So don't worry so much about how to use  had had  as a unit of grammar, they will come together naturally when you want to express the verb ' to have ' in the past perfect. Let's consider a different verb for a moment like  to want .
As I said this is very popular question and you can't afford not to prepare it. Always remember key difference between WHERE and HAVING clause in SQL, if WHERE and HAVING clause is used together, first WHERE clause is applied to filter rows and only after grouping HAVING clause is applied.