  We consider the general Choquard equations $$
  -\Delta u + u = (I_\alpha \ast |u|^p) |u|^{p - 2} u $$ where $I_\alpha$ is a
Riesz potential. We construct minimal action odd solutions for $p \in (\frac{N
+ \alpha}{N}, \frac{N + \alpha}{N - 2})$ and minimal action nodal solutions for
$p \in (2,\frac{N + \alpha}{N - 2})$. We introduce a new minimax principle for
least action nodal solutions and we develop new concentration-compactness
lemmas for sign-changing Palais--Smale sequences. The nonlinear Schr\"odinger
equation, which is the nonlocal counterpart of the Choquard equation, does not
have such solutions.
