A tangled question about php-brackets

Php is a very tangled problem-the brackets do not know why, the original good php program suddenly bad. Yesterday's good program is not good today! For example, if you connect to a database, a database cannot be connected, and you can connect to another database! It is stuck somewhere, and there are no errors when I check various syntaxes! Tangle .... After two days of the test, guan er solved the problem. in the case of the problem, he encountered an empty bracket & #26684;. for example: (abc) changed to: (Empty & php is a very tangled problem-brackets

I don't know why. The original php program suddenly failed. Yesterday's good program is not good today!
For example, if you connect to a database, a database cannot be connected, and you can connect to another database!
It is stuck somewhere, and there are no errors when I check various syntaxes!

Tangle ....

After two days of the test, guan er solved the problem. in the case of the problem, add a space in parentheses.
For example:
(Abc)
Changed:
(Space abc space)

Then, the database can be connected!

The specific reason is unknown! Asking for advice...

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