用php获取外键（语法）

Question

I have the two tables

Create TABLE Comment(
    CommentText TEXT,
    CommentDate DATE NOT NULL,
    Time time,
    PostedBy VARCHAR(30),
    FOREIGN KEY (PostedBy) REFERENCES Employee(Name)
);

Create TABLE Employee(
 Name VARCHAR(30),
 Title VARCHAR(30),
 Onshift BOOLEAN,
 PRIMARY KEY(Name)
);

Now how can I do the following

$Comments =     mysql_query("SELECT * FROM Comment");
$all_comments = array();
while($row = mysql_fetch_array($Comments)) {
    $all_comments[] = $row;
}

foreach($all_comments as $commentrow){
    if($commentrow['PostedBy']){ //Check if The Employee is Onshift 
        Echo("The employee was on shift");
    }
    else{
        Echo("The employee was on shift");
    }
}

I.E given the foreign key (postedby) lookup another value in that foregin keys table (in this case if the boolean if the staff is on shift?)

Answer 1

Your select should be something like

SELECT c.*, e.Name, e.Onshift FROM Comment as c join Employee as e on c.PostedBy = e.Name

And then you can just use

$commentrow['Onshift']