In revising some of my old MySQL scripts, existing syntax works, but
I've no reason why (or where I got it from to begin with).

Ex. Using MySQL in PHP to INSERT a row, the VALUES segment lists some
values like this:

$setsqlcall = "INSERT INTO a_table (
a_name,
a_time )
VALUES (
'".$aname."',
'".$atime."')";

Most examples show simply '$aname' and '$atime'. Why the '".$var."'
syntax - extra pairings of 'double-quote & period ... period &
double-quote' inside paired single-quotes.

In searching for answers I have seen '"+$var+"' too.

Could sometime explain this for me. (Also, if you know where
explanation are to be found for this, I'd like to know that too.)

Thanks, RG

Robert Giden wrote:
The statement is building a complete SQL statement by concatenating ('.'
is the concatenation operator in php, '+' in Visual Basic and maybe
PL/SQL from Oracle) 3 literal strings and 2 program variables.
Apparently a_name and a_time are not simple numeric type (Integer,
Number, Float etc.,) variables so the SQL syntax requires the
apostrophes around the corresponding values. A sample result of the
assignment, ignoring white space, might be:

INSERT INTO a_table (a_name,a_time)
VALUES('Smith','09:18:27')

If you carefully (and this can be hard in a long statement!!!) match up
the quotes (") you will see that they contain the apostrophes so that
php never sees them as php language elements, just part of the various
string literals.