graph/db+sqldb: implement ChanUpdatesInHorizon

Add `ChanUpdatesInHorizon` method to the SQLStore. This lets us run
`TestChanUpdatesInHorizon` against our SQL backends.

sqldb/sqlc/queries/graph.sql

@@ -206,6 +206,62 @@ SELECT
 FROM channel_extra_types cet
 WHERE cet.channel_id = $1;
 
+-- name: GetChannelsByPolicyLastUpdateRange :many
+SELECT
+    sqlc.embed(c),
+    sqlc.embed(n1),
+    sqlc.embed(n2),
+
+    -- Policy 1 (node_id_1)
+    cp1.id AS policy1_id,
+    cp1.node_id AS policy1_node_id,
+    cp1.version AS policy1_version,
+    cp1.timelock AS policy1_timelock,
+    cp1.fee_ppm AS policy1_fee_ppm,
+    cp1.base_fee_msat AS policy1_base_fee_msat,
+    cp1.min_htlc_msat AS policy1_min_htlc_msat,
+    cp1.max_htlc_msat AS policy1_max_htlc_msat,
+    cp1.last_update AS policy1_last_update,
+    cp1.disabled AS policy1_disabled,
+    cp1.inbound_base_fee_msat AS policy1_inbound_base_fee_msat,
+    cp1.inbound_fee_rate_milli_msat AS policy1_inbound_fee_rate_milli_msat,
+    cp1.signature AS policy1_signature,
+
+    -- Policy 2 (node_id_2)
+    cp2.id AS policy2_id,
+    cp2.node_id AS policy2_node_id,
+    cp2.version AS policy2_version,
+    cp2.timelock AS policy2_timelock,
+    cp2.fee_ppm AS policy2_fee_ppm,
+    cp2.base_fee_msat AS policy2_base_fee_msat,
+    cp2.min_htlc_msat AS policy2_min_htlc_msat,
+    cp2.max_htlc_msat AS policy2_max_htlc_msat,
+    cp2.last_update AS policy2_last_update,
+    cp2.disabled AS policy2_disabled,
+    cp2.inbound_base_fee_msat AS policy2_inbound_base_fee_msat,
+    cp2.inbound_fee_rate_milli_msat AS policy2_inbound_fee_rate_milli_msat,
+    cp2.signature AS policy2_signature
+
+FROM channels c
+    JOIN nodes n1 ON c.node_id_1 = n1.id
+    JOIN nodes n2 ON c.node_id_2 = n2.id
+    LEFT JOIN channel_policies cp1
+        ON cp1.channel_id = c.id AND cp1.node_id = c.node_id_1 AND cp1.version = c.version
+    LEFT JOIN channel_policies cp2
+        ON cp2.channel_id = c.id AND cp2.node_id = c.node_id_2 AND cp2.version = c.version
+WHERE c.version = @version
+  AND (
+       (cp1.last_update >= @start_time AND cp1.last_update < @end_time)
+       OR
+       (cp2.last_update >= @start_time AND cp2.last_update < @end_time)
+  )
+ORDER BY
+    CASE
+        WHEN COALESCE(cp1.last_update, 0) >= COALESCE(cp2.last_update, 0)
+            THEN COALESCE(cp1.last_update, 0)
+        ELSE COALESCE(cp2.last_update, 0)
+        END ASC;
+
 -- name: HighestSCID :one
 SELECT scid
 FROM channels