I wonder if it is possible to query a specific part of a comma separated string, something like the following:
$results = mysql_query("SELECT * FROM table1 WHERE $pid=table1.recordA[2] ",$con);
$pid is a number
and recordA contains data like
34,9008,606,,416,2
where i want to check the third part (606)
Thank you in advance
分享 Having comma seperated lists or any data seperation within a mySQL field is frowned upon and is to all extents bad practice.
Rather than looking at querying an element of a delimetered list within a mySQL field consider breaking the field into its own table and then creating an adjacency list to create a 1:many relationship between table1 and it's associated variables.
If you are commited to this route, the simplest method would be to use PHP to manage it as mySQL has very few tools (above and beyond regex / text searches) to drill down to the data you want to extract. $results = explode(',',$query); would create an array of your variables from the returned field allowing you to run as many conditional checks against it as needed.
However, consider adding this to your 'need to re-write / re-think' list. A relational tables structure would allow you to query the database for $pid's value directly as it would be contained within it's own field and linked
If the delimetered variable list is of an inderterminate length or the relationships between the variables are heirarchical you'd be better off searching stackoverflow for information on Directed Acyclic Graphs in mySQL to find a better solution to the problem.
Without knowing the nature or the intended purpose for this script I can't answer in any more detail. I hope this has helped a little.
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