Not even slightly.
As Tony has said, it's vulnerable to SQL Injection: Never concatenate strings to build a SQL command. It leaves you wide open to accidental or deliberate SQL Injection attack which can destroy your entire database. Always use Parameterized queries instead.
When you concatenate strings, you cause problems because SQL receives commands like:
SELECT * FROM MyTable WHERE StreetAddress = 'Baker's Wood'
The quote the user added terminates the string as far as SQL is concerned and you get problems. But it could be worse. If I come along and type this instead: "x';DROP TABLE MyTable;--" Then SQL receives a very different command:
SELECT * FROM MyTable WHERE StreetAddress = 'x';DROP TABLE MyTable;
Which SQL sees as three separate commands:
SELECT * FROM MyTable WHERE StreetAddress = 'x';
A perfectly valid SELECT
DROP TABLE MyTable;
A perfectly valid "delete the table" command
And everything else is a comment.
So it does: selects any matching rows, deletes the table from the DB, and ignores anything else.
So ALWAYS use parameterized queries! Or be prepared to restore your DB from backup frequently. You do take backups regularly, don't you?
And SQL Injection on a login screen? That's just asking for trouble...
Counting the "affected rows" doesn't "prevent SQL injection", it might (if the attacker isn't at all careful) detect it after the fact, but your DB is toast by the point anyway ...
Secondly, You appear to be storing your passwords in plain text, which is about as safe as your code is against SQL injection ... Calling a variable "$hash" does not - in fact - hash it, or apply any salt to the user input to prevent "common lookup" attacks.
So the answer is an overwhelming "No!" - it's not safe. Not even slightly.