There's a problem in the SELECT statement in the WHILE. In the JOIN, there's only one record where ( o1.employee = o2.supervisor ) and it is excluded by the WHERE clause. Can you check the query in the book one more time?

SELECT DISTINCT

o1.chartdepth + 1 ,

o1.employee ,

o1.supervisor

FROM

#org_chart o1

JOIN

#org_chart o2

ON ( o1.employee = o2.supervisor )

WHERE

o1.chartdepth = (

SELECT

MAX(#org_chart.chartdepth)

FROM

#org_chart

)

AND

o1.supervisor <> o1.employee