How to extract the last item from a table name in SQL using regex in PHP?

Question:

I have an SQL query in the format of:

SELECT dt FROM a.b.c WHERE dt = '20210808' LIMIT 10;

The table name in this SQL statement is a.b.c, and I want to extract only the last part of the table name (c). The table name always follows this pattern: schema1.schema2.table_name. My goal is to extract the table_name (the last item) using a regular expression in PHP.

Here’s my current attempt:

$sql = "SELECT dt FROM a.b.c WHERE dt = '20210808' LIMIT 10";
$tmp_table_name_pattern = '/\.([^.]*$)/';
preg_match_all($tmp_table_name_pattern, $sql, $match);
print_r($match);

However, the result I get is:

Array (
    [0] => Array (
        [0] => .c WHERE dt = '20210808' LIMIT 10
    )
    [1] => Array (
        [0] => c WHERE dt = '20210808' LIMIT 10
    )
)

What I expect is to extract only c as the table name. How can I modify my regular expression or PHP code to achieve this?

What I've tried:

• I understand that the regex pattern /\.([^.]*$)/ is matching everything after the last dot, but it also includes extra content after the table name (like WHERE, etc.).
• I need a way to precisely stop at the table name and avoid matching extra parts of the query.

Expected result:

I want the output to be:

Array (
    [0] => Array (
        [0] => c
    )
)

does the regular expression is different between various environments like SHELL、 PHP、JAVA, etc?

Yes, they do differ. Term flavour is used to denote particular version. Examples are

• POSIX Basic Regular Expression (BRE)
• POSIX Extended Regular Expression (ERE)
• Perl Compatible Regular Expressions (PCRE)

If you are interested in flavour used in particular programming language please refer to Regular Expression Engine Comparison Chart