PHP MySQL Syntax quotes dots

Question

I'm really confused about the difference and when should I write like that in MySQL queries between :

`".$variable." `

' ".$variable." '

" '.$variable.' "

'$variable'

In other words what's the rule of quotes, dots ...

[MySQL - when to use single quotes, double quotes, and backticks?](http://stackoverflow.com/questions/11321491/mysql-when-to-use-single-quotes-double-quotes-and-backticks) — John Woo, Apr 16 '13 at 13:29
None of the above, use prepared statements with bind variables — Mark Baker, Apr 16 '13 at 13:29
The dots are PHP string concatenators - nothing to do with MySQL! — deed02392, Apr 16 '13 at 13:41

score 0 · Answer 1 · answered Apr 16 '13 at 13:36

It depends on the way you build your query.

In example, I like to build my queries somewhat like this:

"SELECT name FROM table WHERE table_id='".$id."'"

The double quotes are to close (and later re-open) the statement, single quotes simply mean that it's something of a string (in my example I'm using an integer, but words should be encapsulated in single quotes). The dots are PHP-related: they simply connect/paste stuff together.

Hope my answer has been of use to you :)

score 0 · Accepted Answer · answered Apr 16 '13 at 13:40

This is a variable: $a

This is a string: "hello world"

This is a string: 'hello world'

You can join variables & strings by dot:

$b = $a . "hello" . $a . 'world';

or use variable inside " "

$b = "hello $a world" ;
$b = "hello" . $a . "world" ;
$b = 'hello' . $a . 'world' ;

You can not use variables inside '

` use in mysql for field & table titles.

' use in mysql for variables.

PHP MySQL Syntax quotes dots

2 Answers2