update error messages

Signed-off-by: Richard Chien <[email protected]>

src/frontend/planner_test/tests/testdata/input/temporal_filter.yaml

@@ -26,7 +26,7 @@
 - name: Temporal filter with equal condition
   sql: |-
     create table t1 (ts timestamp with time zone);
-    select * from t1 where date_trunc('week', now())  = date_trunc('week',ts);
+    select * from t1 where date_trunc('week', now()) = date_trunc('week',ts);
   expected_outputs:
     - stream_plan
     - stream_dist_plan
@@ -129,3 +129,9 @@
     select * from t where ts + interval '1 hour' > date_trunc('day', ('2024-07-18 00:00:00+00:00'::timestamptz - ('2024-07-18 00:00:00+00:00'::timestamptz - now())));
   expected_outputs:
     - stream_plan
+- name: Non-monotonic now expression
+  sql: |
+    create table t (ts timestamp with time zone, a int);
+    select * from t where a > extract(hour from now());
+  expected_outputs:
+    - stream_error

src/frontend/planner_test/tests/testdata/output/expr.yaml

@@ -520,7 +520,7 @@
   sql: |
     create table t (v1 timestamp with time zone, v2 timestamp with time zone);
     select * from t where v1 >= now() or v2 >= now();
-  stream_error: Conditions containing now must be of the form `input_expr cmp now() [+- const_expr]` or `now() [+- const_expr] cmp input_expr`, where `input_expr` references a column and contains no `now()`.
+  stream_error: Conditions containing now must be in the form of `input_expr cmp now_expr` or `now_expr cmp input_expr`, where `input_expr` references a column and contains no `now()`, and `now_expr` is a non-decreasing expression contains `now()`.
 - name: now inside HAVING clause
   sql: |
     create table t (v1 timestamp with time zone, v2 int);

src/frontend/planner_test/tests/testdata/output/temporal_filter.yaml

@@ -81,7 +81,7 @@
 - name: Temporal filter with equal condition
   sql: |-
     create table t1 (ts timestamp with time zone);
-    select * from t1 where date_trunc('week', now())  = date_trunc('week',ts);
+    select * from t1 where date_trunc('week', now()) = date_trunc('week',ts);
   stream_plan: |-
     StreamMaterialize { columns: [ts, t1._row_id(hidden), $expr1(hidden)], stream_key: [t1._row_id, $expr1], pk_columns: [t1._row_id, $expr1], pk_conflict: NoCheck }
     └─StreamExchange { dist: HashShard(t1._row_id, $expr1) }
@@ -486,3 +486,8 @@
         └─StreamExchange { dist: Broadcast }
           └─StreamProject { exprs: [DateTrunc('day':Varchar, SubtractWithTimeZone('2024-07-18 00:00:00+00:00':Timestamptz, ('2024-07-18 00:00:00+00:00':Timestamptz - now), 'UTC':Varchar), 'UTC':Varchar) as $expr2] }
             └─StreamNow { output: [now] }
+- name: Non-monotonic now expression
+  sql: |
+    create table t (ts timestamp with time zone, a int);
+    select * from t where a > extract(hour from now());
+  stream_error: Conditions containing now must be in the form of `input_expr cmp now_expr` or `now_expr cmp input_expr`, where `input_expr` references a column and contains no `now()`, and `now_expr` is a non-decreasing expression contains `now()`.

src/frontend/src/optimizer/plan_node/logical_filter.rs

@@ -197,24 +197,11 @@ impl ToStream for LogicalFilter {
         let new_input = self.input().to_stream(ctx)?;
 
         let predicate = self.predicate();
-        let has_now = predicate
-            .conjunctions
-            .iter()
-            .any(|cond| cond.count_nows() > 0);
-        if has_now {
-            if predicate
-                .conjunctions
-                .iter()
-                .any(|expr| expr.count_nows() > 0 && expr.as_now_comparison_cond().is_none())
-            {
-                bail!(
-                    "Conditions containing now must be of the form `input_expr cmp now() [+- const_expr]` or \
-                    `now() [+- const_expr] cmp input_expr`, where `input_expr` references a column \
-                    and contains no `now()`."
-                );
-            }
+        if predicate.conjunctions.iter().any(|cond| cond.has_now()) {
             bail!(
-                "All `now()` exprs were valid, but the condition must have at least one now expr as a lower bound."
+                "Conditions containing now must be in the form of `input_expr cmp now_expr` or \
+                `now_expr cmp input_expr`, where `input_expr` references a column and contains \
+                no `now()`, and `now_expr` is a non-decreasing expression contains `now()`."
             );
         }
         let mut new_logical = self.core.clone();