I'm new to MySQL. Can anyone describe lines below which I get theme from the demo of the jqgrid, what is the meaning of a.id? What is the meaning of these dots?
$SQL = "SELECT a.id, a.invdate, b.name, a.amount,a.tax,a.total,a.note FROM invheader a, clients b WHERE a.client_id=b.client_id ORDER BY $sidx $sord LIMIT $start , $limit";
You've asked several questions here. To address the dots:
a is used as an alias for the
invheader table. This means you can reference that table by the short alias
a instead of the full table name.
a.id refers the the
id column of the
It is generally considered bad practice to simply give your tables the aliases
c, etc. and I would recommend you use something more useful.
I suggest you read some basic MySQL tutorials as this is a fundamental principal.