mysql – Check and count if a column value is used in another column of the same table

I have a table like that

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and looking for a result like this, where the last modification date of a particular identifier is indicated, as well as if the check is 1. Here the identifier 6 is not in the result because the check is 0, so 1 is ignored because the check is 0, so the 9/4/19 entry is displayed in the result.

Then the number of children. it counts the number of times, the parent id is repeated. I really do not want the number of times, the parent id is repeated, but I just want to know if he has a child or not.

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I do not understand how to count children. Remaining I did like that

SELECT id, modified, checks FROM (selects * in the test order by desc modified) as t1 where checks! = 0 group by (id) 

and I had this result

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How to make sure that children count too or just if the id has a child?
How to get a result like this

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