Difference between interpolation (using {} squiggly brackets) and concatenation (., or dot) when constructing an SQL statement

Question

What´s the difference between:

$sql = "select * from {$table}";

and this:

$sql = "select * from ".$table; 

Are there any differences?

Answer 1

The outcome will be the same, but of course you do two fundamental different things:

The first one is variable parsing (which only works in double quoted and heredoc strings), the second one is string concatenation.

Answer 2

There isn't much of a difference other than one uses concatenation and one doesn't.

You can also write it as

$sql = "select * from $table";

You can use {} in your string to refer to objects as well.

If table were a name or array

$sql = "select * from {$table->name}"; //works
$sql = "select * from $table->name"; //works too
$sql = "select * from $table->innerTable->table"; //doesn't work

$sql = "select * from {$table['name']}"; //works
$sql = "select * from $table['name']"; //breaks

I personally use it to increase readability, because I'll always know I'm referring to a variable.