fix(cubesql): Allow to push LIMIT 0 to CubeScan

Author: mcheshkov

rust/cubesql/cubesql/src/compile/rewrite/rules/members.rs

@@ -1621,17 +1621,13 @@ impl MemberRules {
 
             let mut skip_value = None;
             for skip in var_iter!(egraph[subst[skip_var]], LimitSkip) {
-                if skip.unwrap_or_default() > 0 {
-                    skip_value = *skip;
-                    break;
-                }
+                skip_value = *skip;
+                break;
             }
             let mut fetch_value = None;
             for fetch in var_iter!(egraph[subst[fetch_var]], LimitFetch) {
-                if fetch.unwrap_or_default() > 0 {
-                    fetch_value = *fetch;
-                    break;
-                }
+                fetch_value = *fetch;
+                break;
             }
 
             let mut inner_skip_value = None;

rust/cubesql/cubesql/src/compile/test/test_wrapper.rs

@@ -1234,7 +1234,7 @@ async fn select_agg_where_false() {
             segments: Some(vec![]),
             dimensions: Some(vec![]),
             order: Some(vec![]),
-            limit: None,
+            limit: Some(0),
             ungrouped: Some(true),
             ..Default::default()
         }