retrieve row number

<div class="Section1"><p class="MsoNormal"><font face="Verdana" size="2"><span style="font-size:10.0pt;
font-family:Verdana">Hi,</span></font><p class="MsoNormal"><font face="Verdana" size="2"><span style="font-size:10.0pt;
font-family:Verdana"> </span></font><p class="MsoNormal"><font face="Verdana" size="2"><span style="font-size:10.0pt;
font-family:Verdana">Can I retrieve the row number in a select statement? </span></font><p class="MsoNormal"><font
face="Verdana"size="2"><span style="font-size:10.0pt; 
font-family:Verdana">For example : if I have the following table “foo”</span></font><p class="MsoNormal"><font
face="Verdana"size="2"><span style="font-size:10.0pt; 
font-family:Verdana"> </span></font><p class="MsoNormal"><font face="Courier" size="2"><span style="font-size:10.0pt;
font-family:Courier">col1 | col2</span></font><p class="MsoNormal"><font face="Courier" size="2"><span
style="font-size:10.0pt;
font-family:Courier">-----+-----</span></font><p class="MsoNormal"><font face="Courier" size="2"><span
style="font-size:10.0pt;
font-family:Courier"> a   | x</span></font><p class="MsoNormal"><font face="Courier" size="2"><span
style="font-size:10.0pt;
font-family:Courier"> b   | y</span></font><p class="MsoNormal"><font face="Courier" size="2"><span
style="font-size:10.0pt;
font-family:Courier"> c   | z</span></font><p class="MsoNormal"><font face="Courier" size="2"><span
style="font-size:10.0pt;
font-family:Courier"> </span></font><p class="MsoNormal"><font face="Verdana" size="2"><span style="font-size:10.0pt;
font-family:Verdana"> </span></font><p class="MsoNormal"><font face="Verdana" size="2"><span style="font-size:10.0pt;
font-family:Verdana">select ?? as row_number, col1, col2 from foo;</span></font><p class="MsoNormal"><font
face="Verdana"size="2"><span style="font-size:10.0pt; 
font-family:Verdana"> </span></font><p class="MsoNormal"><font face="Verdana" size="2"><span style="font-size:10.0pt;
font-family:Verdana">I should obtain the following result :</span></font><p class="MsoNormal"><font face="Verdana"
size="2"><spanstyle="font-size:10.0pt; 
font-family:Verdana"> </span></font><p class="MsoNormal"><font face="Courier" size="2"><span style="font-size:10.0pt;
font-family:Courier">row_number | col1 | col2</span></font><p class="MsoNormal"><font face="Courier" size="2"><span
style="font-size:10.0pt;
font-family:Courier">-----------+------+-----</span></font><p class="MsoNormal"><font face="Courier" size="2"><span
style="font-size:10.0pt;
font-family:Courier">         1 | a   | x</span></font><p class="MsoNormal"><font face="Courier" size="2"><span
style="font-size:10.0pt;
font-family:Courier">         2 | b   | y</span></font><p class="MsoNormal"><font face="Courier" size="2"><span
style="font-size:10.0pt;
font-family:Courier">         3 | c   | z</span></font><p class="MsoNormal"><font face="Verdana" size="2"><span
style="font-size:10.0pt;
font-family:Verdana"> </span></font><p class="MsoNormal"><font face="Verdana" size="2"><span style="font-size:10.0pt;
font-family:Verdana"> </span></font><p class="MsoNormal"><font face="Verdana" size="2"><span style="font-size:10.0pt;
font-family:Verdana">Thank you</span></font><p class="MsoNormal"><font face="Verdana" size="2"><span
style="font-size:10.0pt;
font-family:Verdana">Pascal</span></font></div>