},
});
+Like elsewhere, literal SQL or literal values can be included by using a
+scalar reference or a literal bind value, and these values will be available
+in the result with C<get_column> (see also
+L<SQL::Abstract/Literal SQL and value type operators>):
+
+ # equivalent SQL: SELECT 1, 'a string', IF(x,1,2) ...
+ columns => [
+ {
+ foo => \1,
+ bar => \q{'a string'},
+ baz => \[ '?', 'IF(x,1,2)' ],
+ }
+ ]
+
=head2 +columns
B<NOTE:> You B<MUST> explicitly quote C<'+columns'> when using this attribute.