query_script_break.html

<p>
<strong>break</strong>: quit loop execution
</p>

<h3>SYNOPSIS</h3>
<p>
<blockquote><pre>while (expression)
{
  if (expression)
    break;
}
</pre></blockquote>
</p>

<h3>DESCRIPTION</h3>
<p> 
<i>break</i> is a QueryScript <a href="query_script_statements.html">statement</a> which,
when invoked, aborts execution of current loop. 
</p>
<p>
<i>break</i> is typically used in an <a href="query_script_if_else.html">if-else</a> statement,
but does not necessarily has to.
</p>
<p>
The <i>break</i> statements quits iteration of the closest wrapping loop, but not any above it.
</p>
<p>
The following loops are all affected by <i>break</i>:
<a href="query_script_while.html">while</a>,
<a href="query_script_loop_while.html">loop-while</a>,
<a href="query_script_foreach.html">foreach</a>.

</p>


<h3>EXAMPLES</h3>

<p>
Break on condition:
<blockquote><pre>set @x := 7;
while (@x > 0)
{
  set @x := @x - 1;
  if (@x = 3)
    break;
}
select @x;

+------+
| @x   |
+------+
|    3 |
+------+
</pre></blockquote>
</p>

<p>
An immediate break:
<blockquote><pre>set @x := 7;
while (true)
{
  set @x := @x - 1;
  break;
}
select @x;

+------+
| @x   |
+------+
|    6 |
+------+
</pre></blockquote>
</p>


<p>
Break from inner loop; outer loop unaffected
<blockquote><pre>set @x := 3;
while (@x > 0)
{
  set @x := @x - 1;
  set @y := 3;
  while (@y > 0)
  {
    set @y := @y -1;
    if (@y < @x)
      break;
    select @x, @y;
  }
}

+------+------+
| @x   | @y   |
+------+------+
|    2 |    2 |
+------+------+

+------+------+
| @x   | @y   |
+------+------+
|    1 |    2 |
+------+------+

+------+------+
| @x   | @y   |
+------+------+
|    1 |    1 |
+------+------+

+------+------+
| @x   | @y   |
+------+------+
|    0 |    2 |
+------+------+

+------+------+
| @x   | @y   |
+------+------+
|    0 |    1 |
+------+------+

+------+------+
| @x   | @y   |
+------+------+
|    0 |    0 |
+------+------+
</pre></blockquote>
</p>


<h3>SEE ALSO</h3>
<a href="query_script_flow_control.html">Flow control</a>

<h3>AUTHOR</h3>
Shlomi Noach