Can database column names start with a number?

[sneakyimp]

Can database column names start with a number or must they start with a letter like php vars? Like my_table.1fieldname ?

Does this vary from db system to db system? Is it considered good/bad form?

[laserlight]

I would say yes, in view that identifiers can be quoted, typically either by double quotes, brackets, or back ticks. I do not know if it is bad form, but it does seem to signal that the design could be improved as the numbering could be trying to represent a one-many or many-many relationship.

[sneakyimp]

good advice thanks!

[Roger_Ramjet]

Only in some databases so it is a bad habit to get into.

Also note this from the manual

It is recommended that you do not use names of the form Me or MeN, where M and N are integers. For example, avoid using 1e or 2e2 as identifiers, because an expression such as 1e+3 is ambiguous. Depending on context, it might be interpreted as the expression 1e + 3 or as the number 1e+3.