Unfortunately MySQL does not have recursive SQL capabilities, so the recursion will have to be done in Perl, which makes this kind of work rather slow since you will have to climb the adjacency tree node-by-node.
in reply to mysql DBI Nested Queries
There are other solutions though, but they all mean that you will have to change your datatables. The most flexible and still fast model is probably the "closure table model". More info on the different options for hierarchical data models can be found at: Models for hierarchical data.
A program should be light and agile, its subroutines connected like a string of pearls. The spirit and intent of the program should be retained throughout. There should be neither too little or too much, neither needless loops nor useless variables, neither lack of structure nor overwhelming rigidity." - The Tao of Programming, 4.1 - Geoffrey James
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