How can I add a boolean column to a `SELECT` statement with a `WHERE` clause and to conditions combined with an `OR` that is 1 if the first condition was met and 0 if the second and not the first condition was met?

As an example take the following table `t` with integer columns:

```
+----+---+---+
| id | a | b |
+----+---+---+
|  1 | 2 | 3 |
|  2 | 3 | 2 |
|  3 | 5 | 2 |
+----+---+---+

```

When I execute the statement `SELECT * FROM t WHERE a<b OR b+1=a;` I get:

```
+----+---+---+
| id | a | b |
+----+---+---+
|  1 | 2 | 3 |
|  2 | 3 | 2 |
+----+---+---+

```

And what I want is an additional column, say `cond`, like

```
+----+---+---+------+
| id | a | b | cond |
+----+---+---+------+
|  1 | 2 | 3 |    1 |
|  2 | 3 | 2 |    0 |
+----+---+---+------+

```

How can this be achieved in MySQL?