diff --git a/postgraphile/postgraphile/__tests__/queries/polymorphic/single-table-items-and-children.mermaid b/postgraphile/postgraphile/__tests__/queries/polymorphic/single-table-items-and-children.mermaid
index 709901ad8..3f9b7d2f4 100644
--- a/postgraphile/postgraphile/__tests__/queries/polymorphic/single-table-items-and-children.mermaid
+++ b/postgraphile/postgraphile/__tests__/queries/polymorphic/single-table-items-and-children.mermaid
@@ -20,22 +20,12 @@ graph TD
     __Value2 --> Access10
     __Value2 --> Access11
     Lambda14{{"Lambda[14∈0] ➊<br />ᐸextractList_grafast_applyᐳ"}}:::plan
-    Constant71{{"Constant[71∈0] ➊<br />ᐸ[ 'PRIMARY_KEY_ASC' ]ᐳ"}}:::plan
-    Constant71 --> Lambda14
+    Constant67{{"Constant[67∈0] ➊<br />ᐸ[ 'PRIMARY_KEY_ASC' ]ᐳ"}}:::plan
+    Constant67 --> Lambda14
     ApplyInput15{{"ApplyInput[15∈0] ➊"}}:::plan
     Constant6 --> ApplyInput15
     Lambda26{{"Lambda[26∈0] ➊<br />ᐸextractList_grafast_applyᐳ"}}:::plan
     Constant6 --> Lambda26
-    ApplyInput27{{"ApplyInput[27∈0] ➊"}}:::plan
-    Constant6 --> ApplyInput27
-    ApplyInput36{{"ApplyInput[36∈0] ➊"}}:::plan
-    Constant6 --> ApplyInput36
-    ApplyInput45{{"ApplyInput[45∈0] ➊"}}:::plan
-    Constant6 --> ApplyInput45
-    ApplyInput54{{"ApplyInput[54∈0] ➊"}}:::plan
-    Constant6 --> ApplyInput54
-    ApplyInput63{{"ApplyInput[63∈0] ➊"}}:::plan
-    Constant6 --> ApplyInput63
     __Value4["__Value[4∈0] ➊<br />ᐸrootValueᐳ"]:::plan
     PgSelect16[["PgSelect[16∈1] ➊<br />ᐸsingle_table_itemsᐳ"]]:::plan
     Object12 & Lambda14 & ApplyInput15 & Connection13 & Constant6 & Constant6 & Constant6 --> PgSelect16
@@ -49,119 +39,55 @@ graph TD
     PgSelectSingle19 --> PgClassExpression20
     PgClassExpression21{{"PgClassExpression[21∈2]<br />ᐸ__single_t...s__.”type”ᐳ"}}:::plan
     PgSelectSingle19 --> PgClassExpression21
-    PgSelect22[["PgSelect[22∈3]<br />ᐸsingle_table_itemsᐳ<br />ᐳSingleTableTopic"]]:::plan
-    Object12 & PgClassExpression20 & Lambda26 & Constant6 & Constant6 & ApplyInput27 --> PgSelect22
-    PgSelect33[["PgSelect[33∈3]<br />ᐸsingle_table_itemsᐳ<br />ᐳSingleTablePost"]]:::plan
-    Object12 & PgClassExpression20 & Lambda26 & Constant6 & Constant6 & ApplyInput36 --> PgSelect33
-    PgSelect42[["PgSelect[42∈3]<br />ᐸsingle_table_itemsᐳ<br />ᐳSingleTableDivider"]]:::plan
-    Object12 & PgClassExpression20 & Lambda26 & Constant6 & Constant6 & ApplyInput45 --> PgSelect42
-    PgSelect51[["PgSelect[51∈3]<br />ᐸsingle_table_itemsᐳ<br />ᐳSingleTableChecklist"]]:::plan
-    Object12 & PgClassExpression20 & Lambda26 & Constant6 & Constant6 & ApplyInput54 --> PgSelect51
-    PgSelect60[["PgSelect[60∈3]<br />ᐸsingle_table_itemsᐳ<br />ᐳSingleTableChecklistItem"]]:::plan
-    Object12 & PgClassExpression20 & Lambda26 & Constant6 & Constant6 & ApplyInput63 --> PgSelect60
+    PgSelect22[["PgSelect[22∈3]<br />ᐸsingle_table_itemsᐳ<br />ᐳSingleTableTopic<br />ᐳSingleTablePost<br />ᐳSingleTableDivider<br />ᐳSingleTableChecklist<br />ᐳSingleTableChecklistItem"]]:::plan
+    Object12 & PgClassExpression20 & Lambda26 & Constant6 & Constant6 & ApplyInput15 --> PgSelect22
     PgSelectRows28[["PgSelectRows[28∈3]"]]:::plan
     PgSelect22 --> PgSelectRows28
-    PgSelectRows37[["PgSelectRows[37∈3]"]]:::plan
-    PgSelect33 --> PgSelectRows37
-    PgSelectRows46[["PgSelectRows[46∈3]"]]:::plan
-    PgSelect42 --> PgSelectRows46
-    PgSelectRows55[["PgSelectRows[55∈3]"]]:::plan
-    PgSelect51 --> PgSelectRows55
-    PgSelectRows64[["PgSelectRows[64∈3]"]]:::plan
-    PgSelect60 --> PgSelectRows64
-    __Item29[/"__Item[29∈4]<br />ᐸ28ᐳ"\]:::itemplan
+    __Item29[/"__Item[29∈4]<br />ᐸ28ᐳ<br />ᐳSingleTableTopic"\]:::itemplan
     PgSelectRows28 ==> __Item29
     PgSelectSingle30{{"PgSelectSingle[30∈4]<br />ᐸsingle_table_itemsᐳ"}}:::plan
     __Item29 --> PgSelectSingle30
-    PgClassExpression31{{"PgClassExpression[31∈4]<br />ᐸ__single_t...ems__.”id”ᐳ"}}:::plan
+    PgClassExpression31{{"PgClassExpression[31∈4]<br />ᐸ__single_t...ems__.”id”ᐳ<br />ᐳSingleTableTopic<br />ᐳSingleTablePost<br />ᐳSingleTableDivider<br />ᐳSingleTableChecklist<br />ᐳSingleTableChecklistItem"}}:::plan
     PgSelectSingle30 --> PgClassExpression31
-    PgClassExpression32{{"PgClassExpression[32∈4]<br />ᐸ__single_t...”position”ᐳ"}}:::plan
+    PgClassExpression32{{"PgClassExpression[32∈4]<br />ᐸ__single_t...”position”ᐳ<br />ᐳSingleTableTopic<br />ᐳSingleTablePost<br />ᐳSingleTableDivider<br />ᐳSingleTableChecklist<br />ᐳSingleTableChecklistItem"}}:::plan
     PgSelectSingle30 --> PgClassExpression32
-    __Item38[/"__Item[38∈6]<br />ᐸ37ᐳ"\]:::itemplan
-    PgSelectRows37 ==> __Item38
-    PgSelectSingle39{{"PgSelectSingle[39∈6]<br />ᐸsingle_table_itemsᐳ"}}:::plan
-    __Item38 --> PgSelectSingle39
-    PgClassExpression40{{"PgClassExpression[40∈6]<br />ᐸ__single_t...ems__.”id”ᐳ"}}:::plan
-    PgSelectSingle39 --> PgClassExpression40
-    PgClassExpression41{{"PgClassExpression[41∈6]<br />ᐸ__single_t...”position”ᐳ"}}:::plan
-    PgSelectSingle39 --> PgClassExpression41
-    __Item47[/"__Item[47∈8]<br />ᐸ46ᐳ"\]:::itemplan
-    PgSelectRows46 ==> __Item47
-    PgSelectSingle48{{"PgSelectSingle[48∈8]<br />ᐸsingle_table_itemsᐳ"}}:::plan
-    __Item47 --> PgSelectSingle48
-    PgClassExpression49{{"PgClassExpression[49∈8]<br />ᐸ__single_t...ems__.”id”ᐳ"}}:::plan
-    PgSelectSingle48 --> PgClassExpression49
-    PgClassExpression50{{"PgClassExpression[50∈8]<br />ᐸ__single_t...”position”ᐳ"}}:::plan
-    PgSelectSingle48 --> PgClassExpression50
-    __Item56[/"__Item[56∈10]<br />ᐸ55ᐳ"\]:::itemplan
-    PgSelectRows55 ==> __Item56
-    PgSelectSingle57{{"PgSelectSingle[57∈10]<br />ᐸsingle_table_itemsᐳ"}}:::plan
-    __Item56 --> PgSelectSingle57
-    PgClassExpression58{{"PgClassExpression[58∈10]<br />ᐸ__single_t...ems__.”id”ᐳ"}}:::plan
-    PgSelectSingle57 --> PgClassExpression58
-    PgClassExpression59{{"PgClassExpression[59∈10]<br />ᐸ__single_t...”position”ᐳ"}}:::plan
-    PgSelectSingle57 --> PgClassExpression59
-    __Item65[/"__Item[65∈12]<br />ᐸ64ᐳ"\]:::itemplan
-    PgSelectRows64 ==> __Item65
-    PgSelectSingle66{{"PgSelectSingle[66∈12]<br />ᐸsingle_table_itemsᐳ"}}:::plan
-    __Item65 --> PgSelectSingle66
-    PgClassExpression67{{"PgClassExpression[67∈12]<br />ᐸ__single_t...ems__.”id”ᐳ"}}:::plan
-    PgSelectSingle66 --> PgClassExpression67
-    PgClassExpression68{{"PgClassExpression[68∈12]<br />ᐸ__single_t...”position”ᐳ"}}:::plan
-    PgSelectSingle66 --> PgClassExpression68
 
     %% define steps
 
     subgraph "Buckets for queries/polymorphic/single-table-items-and-children"
     Bucket0("Bucket 0 (root)"):::bucket
     classDef bucket0 stroke:#696969
-    class Bucket0,__Value2,__Value4,Constant6,Access10,Access11,Object12,Connection13,Lambda14,ApplyInput15,Lambda26,ApplyInput27,ApplyInput36,ApplyInput45,ApplyInput54,ApplyInput63,Constant71 bucket0
-    Bucket1("Bucket 1 (nullableBoundary)<br />Deps: 12, 14, 15, 13, 6, 26, 27, 36, 45, 54, 63<br /><br />ROOT Connectionᐸ9ᐳ[13]<br />1: PgSelect[16]<br />2: PgSelectRows[17]"):::bucket
+    class Bucket0,__Value2,__Value4,Constant6,Access10,Access11,Object12,Connection13,Lambda14,ApplyInput15,Lambda26,Constant67 bucket0
+    Bucket1("Bucket 1 (nullableBoundary)<br />Deps: 12, 14, 15, 13, 6, 26<br /><br />ROOT Connectionᐸ9ᐳ[13]<br />1: PgSelect[16]<br />2: PgSelectRows[17]"):::bucket
     classDef bucket1 stroke:#00bfff
     class Bucket1,PgSelect16,PgSelectRows17 bucket1
-    Bucket2("Bucket 2 (listItem)<br />Deps: 12, 26, 6, 27, 36, 45, 54, 63<br /><br />ROOT __Item{2}ᐸ17ᐳ[18]"):::bucket
+    Bucket2("Bucket 2 (listItem)<br />Deps: 12, 26, 6, 15<br /><br />ROOT __Item{2}ᐸ17ᐳ[18]"):::bucket
     classDef bucket2 stroke:#7f007f
     class Bucket2,__Item18,PgSelectSingle19,PgClassExpression20,PgClassExpression21 bucket2
-    Bucket3("Bucket 3 (polymorphic)<br />SingleTableTopic,SingleTablePost,SingleTableDivider,SingleTableChecklist,SingleTableChecklistItem<br />Deps: 12, 20, 26, 6, 27, 36, 45, 54, 63, 19, 21<br />ᐳSingleTableTopic<br />ᐳSingleTablePost<br />ᐳSingleTableDivider<br />ᐳSingleTableChecklist<br />ᐳSingleTableChecklistItem<br /><br />1: 22, 33, 42, 51, 60<br />2: 28, 37, 46, 55, 64"):::bucket
+    Bucket3("Bucket 3 (polymorphic)<br />SingleTableTopic,SingleTablePost,SingleTableDivider,SingleTableChecklist,SingleTableChecklistItem<br />Deps: 12, 20, 26, 6, 15, 19, 21<br />ᐳSingleTableTopic<br />ᐳSingleTablePost<br />ᐳSingleTableDivider<br />ᐳSingleTableChecklist<br />ᐳSingleTableChecklistItem<br /><br />1: PgSelect[22]<br />2: PgSelectRows[28]"):::bucket
     classDef bucket3 stroke:#ffa500
-    class Bucket3,PgSelect22,PgSelectRows28,PgSelect33,PgSelectRows37,PgSelect42,PgSelectRows46,PgSelect51,PgSelectRows55,PgSelect60,PgSelectRows64 bucket3
+    class Bucket3,PgSelect22,PgSelectRows28 bucket3
     Bucket4("Bucket 4 (listItem)<br /><br />ROOT __Item{4}ᐸ28ᐳ[29]"):::bucket
     classDef bucket4 stroke:#0000ff
     class Bucket4,__Item29,PgSelectSingle30,PgClassExpression31,PgClassExpression32 bucket4
     Bucket5("Bucket 5 (polymorphic)<br />SingleTableTopic,SingleTablePost,SingleTableDivider,SingleTableChecklist,SingleTableChecklistItem<br />Deps: 30, 31, 32<br />ᐳSingleTableTopicᐳSingleTableTopic<br />ᐳSingleTableTopicᐳSingleTablePost<br />ᐳSingleTableTopicᐳSingleTableDivider<br />ᐳSingleTableTopicᐳSingleTableChecklist<br />ᐳSingleTableTopicᐳSingleTableChecklistItem"):::bucket
     classDef bucket5 stroke:#7fff00
     class Bucket5 bucket5
-    Bucket6("Bucket 6 (listItem)<br /><br />ROOT __Item{6}ᐸ37ᐳ[38]"):::bucket
+    Bucket6("Bucket 6 (polymorphic)<br />SingleTableTopic,SingleTablePost,SingleTableDivider,SingleTableChecklist,SingleTableChecklistItem<br />Deps: 30, 31, 32<br />ᐳSingleTablePostᐳSingleTableTopic<br />ᐳSingleTablePostᐳSingleTablePost<br />ᐳSingleTablePostᐳSingleTableDivider<br />ᐳSingleTablePostᐳSingleTableChecklist<br />ᐳSingleTablePostᐳSingleTableChecklistItem"):::bucket
     classDef bucket6 stroke:#ff1493
-    class Bucket6,__Item38,PgSelectSingle39,PgClassExpression40,PgClassExpression41 bucket6
-    Bucket7("Bucket 7 (polymorphic)<br />SingleTableTopic,SingleTablePost,SingleTableDivider,SingleTableChecklist,SingleTableChecklistItem<br />Deps: 39, 40, 41<br />ᐳSingleTablePostᐳSingleTableTopic<br />ᐳSingleTablePostᐳSingleTablePost<br />ᐳSingleTablePostᐳSingleTableDivider<br />ᐳSingleTablePostᐳSingleTableChecklist<br />ᐳSingleTablePostᐳSingleTableChecklistItem"):::bucket
+    class Bucket6 bucket6
+    Bucket7("Bucket 7 (polymorphic)<br />SingleTableTopic,SingleTablePost,SingleTableDivider,SingleTableChecklist,SingleTableChecklistItem<br />Deps: 30, 31, 32<br />ᐳSingleTableDividerᐳSingleTableTopic<br />ᐳSingleTableDividerᐳSingleTablePost<br />ᐳSingleTableDividerᐳSingleTableDivider<br />ᐳSingleTableDividerᐳSingleTableChecklist<br />ᐳSingleTableDividerᐳSingleTableChecklistItem"):::bucket
     classDef bucket7 stroke:#808000
     class Bucket7 bucket7
-    Bucket8("Bucket 8 (listItem)<br /><br />ROOT __Item{8}ᐸ46ᐳ[47]"):::bucket
+    Bucket8("Bucket 8 (polymorphic)<br />SingleTableTopic,SingleTablePost,SingleTableDivider,SingleTableChecklist,SingleTableChecklistItem<br />Deps: 30, 31, 32<br />ᐳSingleTableChecklistᐳSingleTableTopic<br />ᐳSingleTableChecklistᐳSingleTablePost<br />ᐳSingleTableChecklistᐳSingleTableDivider<br />ᐳSingleTableChecklistᐳSingleTableChecklist<br />ᐳSingleTableChecklistᐳSingleTableChecklistItem"):::bucket
     classDef bucket8 stroke:#dda0dd
-    class Bucket8,__Item47,PgSelectSingle48,PgClassExpression49,PgClassExpression50 bucket8
-    Bucket9("Bucket 9 (polymorphic)<br />SingleTableTopic,SingleTablePost,SingleTableDivider,SingleTableChecklist,SingleTableChecklistItem<br />Deps: 48, 49, 50<br />ᐳSingleTableDividerᐳSingleTableTopic<br />ᐳSingleTableDividerᐳSingleTablePost<br />ᐳSingleTableDividerᐳSingleTableDivider<br />ᐳSingleTableDividerᐳSingleTableChecklist<br />ᐳSingleTableDividerᐳSingleTableChecklistItem"):::bucket
+    class Bucket8 bucket8
+    Bucket9("Bucket 9 (polymorphic)<br />SingleTableTopic,SingleTablePost,SingleTableDivider,SingleTableChecklist,SingleTableChecklistItem<br />Deps: 30, 31, 32<br />ᐳSingleTableChecklistItemᐳSingleTableTopic<br />ᐳSingleTableChecklistItemᐳSingleTablePost<br />ᐳSingleTableChecklistItemᐳSingleTableDivider<br />ᐳSingleTableChecklistItemᐳSingleTableChecklist<br />ᐳSingleTableChecklistItemᐳSingleTableChecklistItem"):::bucket
     classDef bucket9 stroke:#ff0000
     class Bucket9 bucket9
-    Bucket10("Bucket 10 (listItem)<br /><br />ROOT __Item{10}ᐸ55ᐳ[56]"):::bucket
-    classDef bucket10 stroke:#ffff00
-    class Bucket10,__Item56,PgSelectSingle57,PgClassExpression58,PgClassExpression59 bucket10
-    Bucket11("Bucket 11 (polymorphic)<br />SingleTableTopic,SingleTablePost,SingleTableDivider,SingleTableChecklist,SingleTableChecklistItem<br />Deps: 57, 58, 59<br />ᐳSingleTableChecklistᐳSingleTableTopic<br />ᐳSingleTableChecklistᐳSingleTablePost<br />ᐳSingleTableChecklistᐳSingleTableDivider<br />ᐳSingleTableChecklistᐳSingleTableChecklist<br />ᐳSingleTableChecklistᐳSingleTableChecklistItem"):::bucket
-    classDef bucket11 stroke:#00ffff
-    class Bucket11 bucket11
-    Bucket12("Bucket 12 (listItem)<br /><br />ROOT __Item{12}ᐸ64ᐳ[65]"):::bucket
-    classDef bucket12 stroke:#4169e1
-    class Bucket12,__Item65,PgSelectSingle66,PgClassExpression67,PgClassExpression68 bucket12
-    Bucket13("Bucket 13 (polymorphic)<br />SingleTableTopic,SingleTablePost,SingleTableDivider,SingleTableChecklist,SingleTableChecklistItem<br />Deps: 66, 67, 68<br />ᐳSingleTableChecklistItemᐳSingleTableTopic<br />ᐳSingleTableChecklistItemᐳSingleTablePost<br />ᐳSingleTableChecklistItemᐳSingleTableDivider<br />ᐳSingleTableChecklistItemᐳSingleTableChecklist<br />ᐳSingleTableChecklistItemᐳSingleTableChecklistItem"):::bucket
-    classDef bucket13 stroke:#3cb371
-    class Bucket13 bucket13
     Bucket0 --> Bucket1
     Bucket1 --> Bucket2
     Bucket2 --> Bucket3
-    Bucket3 --> Bucket4 & Bucket6 & Bucket8 & Bucket10 & Bucket12
-    Bucket4 --> Bucket5
-    Bucket6 --> Bucket7
-    Bucket8 --> Bucket9
-    Bucket10 --> Bucket11
-    Bucket12 --> Bucket13
+    Bucket3 --> Bucket4
+    Bucket4 --> Bucket5 & Bucket6 & Bucket7 & Bucket8 & Bucket9
     end
diff --git a/postgraphile/postgraphile/__tests__/queries/polymorphic/single-table-items-and-children.sql b/postgraphile/postgraphile/__tests__/queries/polymorphic/single-table-items-and-children.sql
index 9df042406..f4eb0f6b4 100644
--- a/postgraphile/postgraphile/__tests__/queries/polymorphic/single-table-items-and-children.sql
+++ b/postgraphile/postgraphile/__tests__/queries/polymorphic/single-table-items-and-children.sql
@@ -4,61 +4,6 @@ select
 from "polymorphic"."single_table_items" as __single_table_items__
 order by __single_table_items__."id" asc;
 
-select __single_table_items_result__.*
-from (select ids.ordinality - 1 as idx, (ids.value->>0)::"int4" as "id0" from json_array_elements($1::json) with ordinality as ids) as __single_table_items_identifiers__,
-lateral (
-  select
-    __single_table_items__."id"::text as "0",
-    __single_table_items__."position"::text as "1",
-    __single_table_items__."type"::text as "2",
-    __single_table_items_identifiers__.idx as "3"
-  from "polymorphic"."single_table_items" as __single_table_items__
-  where (
-    __single_table_items__."parent_id" = __single_table_items_identifiers__."id0"
-  )
-  order by __single_table_items__."id" asc
-) as __single_table_items_result__;
-
-select __single_table_items_result__.*
-from (select ids.ordinality - 1 as idx, (ids.value->>0)::"int4" as "id0" from json_array_elements($1::json) with ordinality as ids) as __single_table_items_identifiers__,
-lateral (
-  select
-    __single_table_items__."id"::text as "0",
-    __single_table_items__."position"::text as "1",
-    __single_table_items__."type"::text as "2",
-    __single_table_items_identifiers__.idx as "3"
-  from "polymorphic"."single_table_items" as __single_table_items__
-  where (
-    __single_table_items__."parent_id" = __single_table_items_identifiers__."id0"
-  )
-  order by __single_table_items__."id" asc
-) as __single_table_items_result__;
-
-select __single_table_items_result__.*
-from (select ids.ordinality - 1 as idx, (ids.value->>0)::"int4" as "id0" from json_array_elements($1::json) with ordinality as ids) as __single_table_items_identifiers__,
-lateral (
-  select
-    __single_table_items__."id"::text as "0",
-    __single_table_items__."position"::text as "1",
-    __single_table_items__."type"::text as "2",
-    __single_table_items_identifiers__.idx as "3"
-  from "polymorphic"."single_table_items" as __single_table_items__
-  where (
-    __single_table_items__."parent_id" = __single_table_items_identifiers__."id0"
-  )
-  order by __single_table_items__."id" asc
-) as __single_table_items_result__;
-
-select
-  __single_table_items__."id"::text as "0",
-  __single_table_items__."position"::text as "1",
-  __single_table_items__."type"::text as "2"
-from "polymorphic"."single_table_items" as __single_table_items__
-where (
-  __single_table_items__."parent_id" = $1::"int4"
-)
-order by __single_table_items__."id" asc;
-
 select __single_table_items_result__.*
 from (select ids.ordinality - 1 as idx, (ids.value->>0)::"int4" as "id0" from json_array_elements($1::json) with ordinality as ids) as __single_table_items_identifiers__,
 lateral (