diff --git a/src/backend/partitioning/partprune.c b/src/backend/partitioning/partprune.c
index badd31a44c..0543f6fffc 100644
--- a/src/backend/partitioning/partprune.c
+++ b/src/backend/partitioning/partprune.c
@@ -1397,6 +1397,27 @@ gen_prune_steps_from_opexps(GeneratePruningStepsContext *context,
 						List	   *prefix = NIL;
 						List	   *pc_steps;
 
+						/*
+						 * If this is a clause for the first partition key,
+						 * there are no preceding expressions; generate a
+						 * pruning step without a prefix.
+						 */
+						if (pc->keyno == 0)
+						{
+							Assert(pc->op_strategy == strat);
+							pc_steps = get_steps_using_prefix(context, strat,
+															  pc->op_is_ne,
+															  pc->expr,
+															  pc->cmpfn,
+															  0,
+															  NULL,
+															  NIL);
+							opsteps = list_concat(opsteps, pc_steps);
+							continue;
+						}
+
+						Assert(pc->keyno > 0);
+
 						/*
 						 * Expressions from = clauses can always be in the
 						 * prefix, provided they're from an earlier key.
@@ -1455,19 +1476,29 @@ gen_prune_steps_from_opexps(GeneratePruningStepsContext *context,
 						 * generate multiple steps, one for each combination
 						 * of the expressions for different keys.
 						 *
+						 * If prefix contains no clauses, we would not have
+						 * clauses for a valid subset of the partition keys
+						 * for the remaining clauses; give up on generating
+						 * pruning steps further for the strategy.
+						 *
 						 * Note that we pass NULL for step_nullkeys, because
 						 * we don't search list/range partition bounds where
 						 * some keys are NULL.
 						 */
-						Assert(pc->op_strategy == strat);
-						pc_steps = get_steps_using_prefix(context, strat,
-														  pc->op_is_ne,
-														  pc->expr,
-														  pc->cmpfn,
-														  pc->keyno,
-														  NULL,
-														  prefix);
-						opsteps = list_concat(opsteps, pc_steps);
+						if (prefix)
+						{
+							Assert(pc->op_strategy == strat);
+							pc_steps = get_steps_using_prefix(context, strat,
+															  pc->op_is_ne,
+															  pc->expr,
+															  pc->cmpfn,
+															  pc->keyno,
+															  NULL,
+															  prefix);
+							opsteps = list_concat(opsteps, pc_steps);
+						}
+						else
+							break;
 					}
 				}
 				break;
diff --git a/src/test/regress/expected/partition_prune.out b/src/test/regress/expected/partition_prune.out
index 4315e8e0a3..d0f3b4525d 100644
--- a/src/test/regress/expected/partition_prune.out
+++ b/src/test/regress/expected/partition_prune.out
@@ -3671,3 +3671,12 @@ explain (costs off) update listp1 set a = 1 where a = 2;
 reset constraint_exclusion;
 reset enable_partition_pruning;
 drop table listp;
+create table prefix_test (a int, b varchar)
+partition by range(a, b);
+create table prefix_test1 partition of prefix_test
+for values from (1, 'a') to (1, 'b');
+select * from prefix_test where a <= 1 and b = 'a' ;
+ a | b 
+---+---
+(0 rows)
+
diff --git a/src/test/regress/sql/partition_prune.sql b/src/test/regress/sql/partition_prune.sql
index 6658455a74..3581b6a0d3 100644
--- a/src/test/regress/sql/partition_prune.sql
+++ b/src/test/regress/sql/partition_prune.sql
@@ -1050,3 +1050,11 @@ reset constraint_exclusion;
 reset enable_partition_pruning;
 
 drop table listp;
+
+create table prefix_test (a int, b varchar)
+partition by range(a, b);
+
+create table prefix_test1 partition of prefix_test
+for values from (1, 'a') to (1, 'b');
+
+select * from prefix_test where a <= 1 and b = 'a' ;