Trigonometric functions use radians, not degrees. When a NULL, or undefined, value is encountered in the FITS table, the expression will evaluate to NULL unless the undefined value is not actually required for evaluation, eg. The following type casting operators are available, where the inclosing parentheses are required and taken from the C language usage. In all the representations, an x or X is allowed in the mask as a wild card. Note that the x represents a different number of wild card bits in each representation.
All representations are case insensitive.
To construct the boolean expression using the mask as the boolean equal operator discribed above on a bit table column. All of these operators result in a bit field which can then be used with the equal operator. Strings can be concatenated this way, too. Vector Columns Vector columns can also be used in building the expression. No special syntax is required if one wants to operate on all elements of the vector.