Two simple MySQL statements causing syntax error - sql

Question

I'm confounded. The following MySQL query:
SET #a := 0;
SELECT *
FROM users;
Gives the error:
Invalid query: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'SELECT * FROM users' at line 2`
When I switch the order of the statements, I get the same error, again on line 2 (even though I switched them)
However, either line by themselves runs fine. What could possibly cause this?

Answer 1

I bet you're trying to perform this query in the mysql_query() (or some similar function from any programming language), but it accepts only single query. So the solution is to split this queries into 2 calls.

Answer 2

you can do it in one query as follows:
The trick
select #a:=#a+1, u.*
from
users u
join (select #a:=0) a
or be adventerous and use a stored procedure so it's always a single call :P
Stored procedure
drop procedure if exists list_users;
delimiter #
create procedure list_users()
begin
set #a = 0;
select #a:=#a+1, u.* from users u;
end #
delimiter ;
call list_users();
PHP script
$conn = new mysqli("localhost", "foo_dbo", "pass", "foo_db", 3306);
$result = $conn->query("call list_users()");
while($row = $result->fetch_assoc()){
...
}
$result->close();
$conn->close();