diff --git a/queries/orderbook/barn_batch_rewards.sql b/queries/orderbook/barn_batch_rewards.sql
index bb86f554..1f259aea 100644
--- a/queries/orderbook/barn_batch_rewards.sql
+++ b/queries/orderbook/barn_batch_rewards.sql
@@ -25,7 +25,9 @@ order_data as (
         kind,
         app_data
     from orders
-    union all
+    union distinct -- A _distinct_ union is needed since orders can appear in the normal orders
+    -- table and in the jit orders table. Since the uid is otherwise unique, no valid order is
+    -- removed by the _distinct_ union.
     select
         uid,
         sell_token,
diff --git a/queries/orderbook/order_data.sql b/queries/orderbook/order_data.sql
index a7e4f6ab..90661910 100644
--- a/queries/orderbook/order_data.sql
+++ b/queries/orderbook/order_data.sql
@@ -36,7 +36,9 @@ order_data as (
         kind,
         app_data
     from orders
-    union all
+    union distinct -- A _distinct_ union is needed since orders can appear in the normal orders
+    -- table and in the jit orders table. Since the uid is otherwise unique, no valid order is
+    -- removed by the _distinct_ union.
     select
         uid,
         sell_token,
diff --git a/queries/orderbook/prod_batch_rewards.sql b/queries/orderbook/prod_batch_rewards.sql
index cc6f2e55..e2aa5839 100644
--- a/queries/orderbook/prod_batch_rewards.sql
+++ b/queries/orderbook/prod_batch_rewards.sql
@@ -25,7 +25,9 @@ order_data as (
         kind,
         app_data
     from orders
-    union all
+    union distinct -- A _distinct_ union is needed since orders can appear in the normal orders
+    -- table and in the jit orders table. Since the uid is otherwise unique, no valid order is
+    -- removed by the _distinct_ union.
     select
         uid,
         sell_token,