mysql_query isnt working

programming
1

I have a form that is suposed to insert a new record in to the db when someone clicks on the submit button

I think i have it set u p correctly her is my page


<?php
 if (isset ($_POST['post'])){
    
    $tanounce = $_POST['announcements'];
    $announce = trim($tannounce);
                if ( !empty($announce) ) 
            {    
mysql_query("INSERT INTO `impactathletics`.`team` (`announcements`)
WHERE team_id = '1' 
VALUES ('$announce')");
              
             }
    } 
?>
<html>
<head>
</head>
<body>
            <form method="post" action="<?php echo $_SERVER['PHP_SELF'] ?>">
                <textarea name="announcements" cols="45" rows="5"></textarea>
                <br />
                <input type="submit" value="Submit" />
                <br />
            </form>
</body>
</heml>

can any one see the problem?
side note the table its supposed to be inserted into already contains info. Will it add to the field? or will it drop it.