PHP是否在phpMyAdmin中重复具有相同名称的变量，或者它是否与print_r有关？

Question

I was looking at the results of a mysql join in phpmyadmin, and comparing it to the php print_r dump, and noticed that the print_r seems to only use the first (row)"id" variable it comes to, and skips the second one. Is there a reason why the print_r wouldn't put something like a 'tablename."id"' instead of just eliminating the second tables "id" value?

PHPmyADMIN head dump:

• id inst_id zip id inst_id skill

PHP sample dump:

• Array ( [id] => 1 [inst_id] => 1 [zip] => 23456 [skill] => meow )

Answer 1

print_r just prints the array as it is, and apparently it only has those 4 indexes with the specified values.

The problem is in the query itself. Table names or table aliases are not returned in the field name, so you get two fields named id. Since an array cannot have the same key twice, one of the two is just skipped.

So to solve it, change the query by specifying an alias for the field itself:

SELECT
  t1.id as t1_id, -- Key will be t1_id
  t2.id as t2_id, -- Key will be t2_id
  .. other fields ..
FROM
  .. etcetera ...