sql_function! instead. See
CHANGELOG.md for migration instructions
Declare a 0 argument SQL function for use in your code. This will generate a
unit struct, which is an expression representing calling this function. See
now for example output.
no_arg_sql_function!(now, sql_types::Timestamp, "Represents the SQL NOW() function");
You can optionally pass the name of a trait, as a constraint for backends which support the function.