Class Case

tortoise/expressions.py:704–734

Case expression. :param args: When objects :param default: value for 'CASE WHEN ... THEN ... ELSE END'

class Case(Expression):
    """
    Case expression.

    :param args: When objects
    :param default: value for 'CASE WHEN ... THEN ... ELSE <default> END'
    """

    def __init__(
        self,
        *args: When,
        default: str | F | CombinedExpression | Function | None = None,
    ) -> None:
        self.args = args
        self.default = default

    def resolve(self, resolve_context: ResolveContext) -> ResolveResult:
        case = PypikaCase()
        for arg in self.args:
            if not isinstance(arg, When):
                raise TypeError("expected When objects as args")
            when = arg.resolve(resolve_context)
            when_term = cast(_WhenThen, when.term)
            case = case.when(when_term.when, when_term.then)

        if isinstance(self.default, Expression):
            case = case.else_(self.default.resolve(resolve_context).term)
        else:
            case = case.else_(Term.wrap_constant(self.default))

        return ResolveResult(term=case)