Frequently Asked Questions

What are the units of the value on the right in Xmatch(a,b) < 3.5 ?
There are no units for this value. It is the value you would like the chisquare less than.

My query like 'Select a.jm -b.j from ..' does not work why ?
You need to alias the pseudo column like 'Select a.jm -b.j as diffjmjfrom ..'

My query like 'Select t.* from ..' does not work why ?
ADQL0.7.4 has certain limitaions in colum names if the table contains an illegal name the query will break. Some limitaitons of ADQL are :

• columns with '_'
• colums named EXP (such as in Rosat)
• functions with arithmatic params
• functions with function params.