We don't know how to get the value we want efficiently in the data nested by the number of layers.

problem description

if I have a nesting of three tiers of data and download the information that needs to take one of the pieces of composite data, maybe we need to do a three-tier for loop or recursion. How can we achieve this requirement with the lowest energy consumption

the environmental background of the problems and what methods you have tried

for loop, recursive

related codes

/ / Please paste the code text below (do not replace the code with pictures)

what result do you expect? What is the error message actually seen?

Jul.06,2021
MySQL Query : SELECT * FROM `codeshelper`.`v9_news` WHERE status=99 AND catid='6' ORDER BY rand() LIMIT 5
MySQL Error : Disk full (/tmp/#sql-temptable-64f5-1bee220-31355.MAI); waiting for someone to free some space... (errno: 28 "No space left on device")
MySQL Errno : 1021
Message : Disk full (/tmp/#sql-temptable-64f5-1bee220-31355.MAI); waiting for someone to free some space... (errno: 28 "No space left on device")
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