From 6a09ba9f17d3ab187987cef14049f9abea315c86 Mon Sep 17 00:00:00 2001
From: Scott Anderson <sanderson@users.noreply.github.com>
Date: Thu, 25 Aug 2022 09:00:52 -0600
Subject: [PATCH] Update 'exists' guide with correct static example (#4388)

* update exists guide with correct static example, closes #4387

* port exists changes back to all exists guides
---
 content/influxdb/v1.7/flux/guides/exists.md   | 96 ++++++++++++-------
 content/influxdb/v1.8/flux/guides/exists.md   | 96 ++++++++++++-------
 .../influxdb/v2.0/query-data/flux/exists.md   | 92 +++++++++++-------
 .../influxdb/v2.1/query-data/flux/exists.md   | 48 +++++++---
 .../influxdb/v2.2/query-data/flux/exists.md   | 48 +++++++---
 .../influxdb/v2.3/query-data/flux/exists.md   | 48 +++++++---
 .../influxdb/v2.4/query-data/flux/exists.md   | 51 +++++++---
 7 files changed, 322 insertions(+), 157 deletions(-)

diff --git a/content/influxdb/v1.7/flux/guides/exists.md b/content/influxdb/v1.7/flux/guides/exists.md
index fafb64a65..e70405e47 100644
--- a/content/influxdb/v1.7/flux/guides/exists.md
+++ b/content/influxdb/v1.7/flux/guides/exists.md
@@ -3,8 +3,8 @@ title: Check if a value exists
 seotitle: Use Flux to check if a value exists
 list_title: Exists
 description: >
-  Use the Flux `exists` operator to check if a record contains a key or if that
-  key's value is `null`.
+  Use the `exists` operator to check if a row record contains a column or if a
+  column's value is _null_.
 menu:
   influxdb_1_7:
     name: Exists
@@ -20,63 +20,87 @@ list_code_example: |
   ```
 ---
 
-Use the Flux `exists` operator to check if a record contains a key or if that
-key's value is `null`.
+Use the `exists` operator to check if a row record contains a column or if a
+column's value is _null_.
 
 ```js
-p = {firstName: "John", lastName: "Doe", age: 42}
-
-exists p.firstName
-// Returns true
-
-exists p.height
-// Returns false
+(r) => exists r.column
 ```
 
 If you're just getting started with Flux queries, check out the following:
 
-- [Get started with Flux](/influxdb/v1.7/flux/get-started/) for a conceptual overview of Flux and parts of a Flux query.
-- [Execute queries](/influxdb/v1.7/flux/guides/execute-queries/) to discover a variety of ways to run your queries.
+- [Get started with Flux](/{{< latest "flux" >}}/get-started/) for a conceptual overview of Flux and parts of a Flux query.
+- [Execute queries](/influxdb/v2.4/query-data/execute-queries/) to discover a variety of ways to run your queries.
 
 Use `exists` with row functions (
 [`filter()`](/{{< latest "flux" >}}/stdlib/universe/filter/),
 [`map()`](/{{< latest "flux" >}}/stdlib/universe/map/),
 [`reduce()`](/{{< latest "flux" >}}/stdlib/universe/reduce/))
-to check if a row includes a column or if the value for that column is `null`.
+to check if a row includes a column or if the value for that column is _null_.
 
 #### Filter null values
+
 ```js
-from(bucket: "db/rp")
-  |> range(start: -5m)
-  |> filter(fn: (r) => exists r._value)
+from(bucket: "example-bucket")
+    |> range(start: -5m)
+    |> filter(fn: (r) => exists r._value)
 ```
 
 #### Map values based on existence
+
 ```js
 from(bucket: "default")
-  |> range(start: -30s)
-  |> map(fn: (r) => ({
-      r with
-      human_readable:
-        if exists r._value then "${r._field} is ${string(v:r._value)}."
-        else "${r._field} has no value."
-  }))
+    |> range(start: -30s)
+    |> map(
+        fn: (r) => ({r with
+            human_readable: if exists r._value then
+                "${r._field} is ${string(v: r._value)}."
+            else
+                "${r._field} has no value.",
+        }),
+    )
 ```
 
 #### Ignore null values in a custom aggregate function
+
 ```js
-customSumProduct = (tables=<-) =>
-  tables
+customSumProduct = (tables=<-) => tables
     |> reduce(
-      identity: {sum: 0.0, product: 1.0},
-      fn: (r, accumulator) => ({
-        r with
-        sum:
-          if exists r._value then r._value + accumulator.sum
-          else accumulator.sum,
-        product:
-          if exists r._value then r.value * accumulator.product
-          else accumulator.product
-      })
+        identity: {sum: 0.0, product: 1.0},
+        fn: (r, accumulator) => ({r with
+            sum: if exists r._value then
+                r._value + accumulator.sum
+            else
+                accumulator.sum,
+            product: if exists r._value then
+                r.value * accumulator.product
+            else
+                accumulator.product,
+        }),
     )
 ```
+
+#### Check if a statically defined record contains a key
+
+When you use the [record literal syntax](/flux/v0.x/data-types/composite/record/#record-syntax)
+to statically define a record, Flux knows the record type and what keys to expect.
+
+- If the key exists in the static record, `exists` returns `true`.
+- If the key does not exist in the static record, because the record type is
+  statically known, `exists` returns an error.
+
+```js
+import "internal/debug"
+
+p = {
+    firstName: "John",
+    lastName: "Doe",
+    age: 42,
+}
+
+exists p.firstName
+// Returns true
+
+exists p.height
+// Returns "error: record is missing label height"
+```
diff --git a/content/influxdb/v1.8/flux/guides/exists.md b/content/influxdb/v1.8/flux/guides/exists.md
index 27a9085e7..13a2469b7 100644
--- a/content/influxdb/v1.8/flux/guides/exists.md
+++ b/content/influxdb/v1.8/flux/guides/exists.md
@@ -3,8 +3,8 @@ title: Check if a value exists
 seotitle: Use Flux to check if a value exists
 list_title: Exists
 description: >
-  Use the Flux `exists` operator to check if a record contains a key or if that
-  key's value is `null`.
+  Use the `exists` operator to check if a row record contains a column or if a
+  column's value is _null_.
 menu:
   influxdb_1_8:
     name: Exists
@@ -20,63 +20,87 @@ list_code_example: |
   ```
 ---
 
-Use the Flux `exists` operator to check if a record contains a key or if that
-key's value is `null`.
+Use the `exists` operator to check if a row record contains a column or if a
+column's value is _null_.
 
 ```js
-p = {firstName: "John", lastName: "Doe", age: 42}
-
-exists p.firstName
-// Returns true
-
-exists p.height
-// Returns false
+(r) => exists r.column
 ```
 
 If you're just getting started with Flux queries, check out the following:
 
-- [Get started with Flux](/influxdb/v1.8/flux/get-started/) for a conceptual overview of Flux and parts of a Flux query.
-- [Execute queries](/influxdb/v1.8/flux/guides/execute-queries/) to discover a variety of ways to run your queries.
+- [Get started with Flux](/{{< latest "flux" >}}/get-started/) for a conceptual overview of Flux and parts of a Flux query.
+- [Execute queries](/influxdb/v2.4/query-data/execute-queries/) to discover a variety of ways to run your queries.
 
 Use `exists` with row functions (
 [`filter()`](/{{< latest "flux" >}}/stdlib/universe/filter/),
 [`map()`](/{{< latest "flux" >}}/stdlib/universe/map/),
 [`reduce()`](/{{< latest "flux" >}}/stdlib/universe/reduce/))
-to check if a row includes a column or if the value for that column is `null`.
+to check if a row includes a column or if the value for that column is _null_.
 
 #### Filter null values
+
 ```js
-from(bucket: "db/rp")
-  |> range(start: -5m)
-  |> filter(fn: (r) => exists r._value)
+from(bucket: "example-bucket")
+    |> range(start: -5m)
+    |> filter(fn: (r) => exists r._value)
 ```
 
 #### Map values based on existence
+
 ```js
 from(bucket: "default")
-  |> range(start: -30s)
-  |> map(fn: (r) => ({
-      r with
-      human_readable:
-        if exists r._value then "${r._field} is ${string(v:r._value)}."
-        else "${r._field} has no value."
-  }))
+    |> range(start: -30s)
+    |> map(
+        fn: (r) => ({r with
+            human_readable: if exists r._value then
+                "${r._field} is ${string(v: r._value)}."
+            else
+                "${r._field} has no value.",
+        }),
+    )
 ```
 
 #### Ignore null values in a custom aggregate function
+
 ```js
-customSumProduct = (tables=<-) =>
-  tables
+customSumProduct = (tables=<-) => tables
     |> reduce(
-      identity: {sum: 0.0, product: 1.0},
-      fn: (r, accumulator) => ({
-        r with
-        sum:
-          if exists r._value then r._value + accumulator.sum
-          else accumulator.sum,
-        product:
-          if exists r._value then r.value * accumulator.product
-          else accumulator.product
-      })
+        identity: {sum: 0.0, product: 1.0},
+        fn: (r, accumulator) => ({r with
+            sum: if exists r._value then
+                r._value + accumulator.sum
+            else
+                accumulator.sum,
+            product: if exists r._value then
+                r.value * accumulator.product
+            else
+                accumulator.product,
+        }),
     )
 ```
+
+#### Check if a statically defined record contains a key
+
+When you use the [record literal syntax](/flux/v0.x/data-types/composite/record/#record-syntax)
+to statically define a record, Flux knows the record type and what keys to expect.
+
+- If the key exists in the static record, `exists` returns `true`.
+- If the key does not exist in the static record, because the record type is
+  statically known, `exists` returns an error.
+
+```js
+import "internal/debug"
+
+p = {
+    firstName: "John",
+    lastName: "Doe",
+    age: 42,
+}
+
+exists p.firstName
+// Returns true
+
+exists p.height
+// Returns "error: record is missing label height"
+```
diff --git a/content/influxdb/v2.0/query-data/flux/exists.md b/content/influxdb/v2.0/query-data/flux/exists.md
index 60dc55cec..ed0df123b 100644
--- a/content/influxdb/v2.0/query-data/flux/exists.md
+++ b/content/influxdb/v2.0/query-data/flux/exists.md
@@ -3,8 +3,8 @@ title: Check if a value exists
 seotitle: Use Flux to check if a value exists
 list_title: Exists
 description: >
-  Use the Flux `exists` operator to check if a record contains a key or if that
-  key's value is `null`.
+  Use the `exists` operator to check if a row record contains a column or if a
+  column's value is _null_.
 influxdb/v2.0/tags: [exists]
 menu:
   influxdb_2_0:
@@ -24,63 +24,87 @@ list_code_example: |
   ```
 ---
 
-Use the Flux `exists` operator to check if a record contains a key or if that
-key's value is `null`.
+Use the `exists` operator to check if a row record contains a column or if a
+column's value is _null_.
 
 ```js
-p = {firstName: "John", lastName: "Doe", age: 42}
-
-exists p.firstName
-// Returns true
-
-exists p.height
-// Returns false
+(r) => exists r.column
 ```
 
 If you're just getting started with Flux queries, check out the following:
 
 - [Get started with Flux](/{{< latest "flux" >}}/get-started/) for a conceptual overview of Flux and parts of a Flux query.
-- [Execute queries](/influxdb/v2.0/query-data/execute-queries/) to discover a variety of ways to run your queries.
+- [Execute queries](/influxdb/v2.4/query-data/execute-queries/) to discover a variety of ways to run your queries.
 
 Use `exists` with row functions (
 [`filter()`](/{{< latest "flux" >}}/stdlib/universe/filter/),
 [`map()`](/{{< latest "flux" >}}/stdlib/universe/map/),
 [`reduce()`](/{{< latest "flux" >}}/stdlib/universe/reduce/))
-to check if a row includes a column or if the value for that column is `null`.
+to check if a row includes a column or if the value for that column is _null_.
 
 #### Filter null values
+
 ```js
 from(bucket: "example-bucket")
-  |> range(start: -5m)
-  |> filter(fn: (r) => exists r._value)
+    |> range(start: -5m)
+    |> filter(fn: (r) => exists r._value)
 ```
 
 #### Map values based on existence
+
 ```js
 from(bucket: "default")
-  |> range(start: -30s)
-  |> map(fn: (r) => ({
-      r with
-      human_readable:
-        if exists r._value then "${r._field} is ${string(v:r._value)}."
-        else "${r._field} has no value."
-  }))
+    |> range(start: -30s)
+    |> map(
+        fn: (r) => ({r with
+            human_readable: if exists r._value then
+                "${r._field} is ${string(v: r._value)}."
+            else
+                "${r._field} has no value.",
+        }),
+    )
 ```
 
 #### Ignore null values in a custom aggregate function
+
 ```js
-customSumProduct = (tables=<-) =>
-  tables
+customSumProduct = (tables=<-) => tables
     |> reduce(
-      identity: {sum: 0.0, product: 1.0},
-      fn: (r, accumulator) => ({
-        r with
-        sum:
-          if exists r._value then r._value + accumulator.sum
-          else accumulator.sum,
-        product:
-          if exists r._value then r.value * accumulator.product
-          else accumulator.product
-      })
+        identity: {sum: 0.0, product: 1.0},
+        fn: (r, accumulator) => ({r with
+            sum: if exists r._value then
+                r._value + accumulator.sum
+            else
+                accumulator.sum,
+            product: if exists r._value then
+                r.value * accumulator.product
+            else
+                accumulator.product,
+        }),
     )
 ```
+
+#### Check if a statically defined record contains a key
+
+When you use the [record literal syntax](/flux/v0.x/data-types/composite/record/#record-syntax)
+to statically define a record, Flux knows the record type and what keys to expect.
+
+- If the key exists in the static record, `exists` returns `true`.
+- If the key does not exist in the static record, because the record type is
+  statically known, `exists` returns an error.
+
+```js
+import "internal/debug"
+
+p = {
+    firstName: "John",
+    lastName: "Doe",
+    age: 42,
+}
+
+exists p.firstName
+// Returns true
+
+exists p.height
+// Returns "error: record is missing label height"
+```
diff --git a/content/influxdb/v2.1/query-data/flux/exists.md b/content/influxdb/v2.1/query-data/flux/exists.md
index 2af8d69c2..a7d7fd909 100644
--- a/content/influxdb/v2.1/query-data/flux/exists.md
+++ b/content/influxdb/v2.1/query-data/flux/exists.md
@@ -3,8 +3,8 @@ title: Check if a value exists
 seotitle: Use Flux to check if a value exists
 list_title: Exists
 description: >
-  Use the Flux `exists` operator to check if a record contains a key or if that
-  key's value is `null`.
+  Use the `exists` operator to check if a row record contains a column or if a
+  column's value is _null_.
 influxdb/v2.1/tags: [exists]
 menu:
   influxdb_2_1:
@@ -24,31 +24,26 @@ list_code_example: |
   ```
 ---
 
-Use the Flux `exists` operator to check if a record contains a key or if that
-key's value is `null`.
+Use the `exists` operator to check if a row record contains a column or if a
+column's value is _null_.
 
 ```js
-p = {firstName: "John", lastName: "Doe", age: 42}
-
-exists p.firstName
-// Returns true
-
-exists p.height
-// Returns false
+(r) => exists r.column
 ```
 
 If you're just getting started with Flux queries, check out the following:
 
 - [Get started with Flux](/{{< latest "flux" >}}/get-started/) for a conceptual overview of Flux and parts of a Flux query.
-- [Execute queries](/influxdb/v2.1/query-data/execute-queries/) to discover a variety of ways to run your queries.
+- [Execute queries](/influxdb/v2.4/query-data/execute-queries/) to discover a variety of ways to run your queries.
 
 Use `exists` with row functions (
 [`filter()`](/{{< latest "flux" >}}/stdlib/universe/filter/),
 [`map()`](/{{< latest "flux" >}}/stdlib/universe/map/),
 [`reduce()`](/{{< latest "flux" >}}/stdlib/universe/reduce/))
-to check if a row includes a column or if the value for that column is `null`.
+to check if a row includes a column or if the value for that column is _null_.
 
 #### Filter null values
+
 ```js
 from(bucket: "example-bucket")
     |> range(start: -5m)
@@ -56,6 +51,7 @@ from(bucket: "example-bucket")
 ```
 
 #### Map values based on existence
+
 ```js
 from(bucket: "default")
     |> range(start: -30s)
@@ -70,6 +66,7 @@ from(bucket: "default")
 ```
 
 #### Ignore null values in a custom aggregate function
+
 ```js
 customSumProduct = (tables=<-) => tables
     |> reduce(
@@ -86,3 +83,28 @@ customSumProduct = (tables=<-) => tables
         }),
     )
 ```
+
+#### Check if a statically defined record contains a key
+
+When you use the [record literal syntax](/flux/v0.x/data-types/composite/record/#record-syntax)
+to statically define a record, Flux knows the record type and what keys to expect.
+
+- If the key exists in the static record, `exists` returns `true`.
+- If the key does not exist in the static record, because the record type is
+  statically known, `exists` returns an error.
+
+```js
+import "internal/debug"
+
+p = {
+    firstName: "John",
+    lastName: "Doe",
+    age: 42,
+}
+
+exists p.firstName
+// Returns true
+
+exists p.height
+// Returns "error: record is missing label height"
+```
diff --git a/content/influxdb/v2.2/query-data/flux/exists.md b/content/influxdb/v2.2/query-data/flux/exists.md
index ec900c312..ebfc1aedb 100644
--- a/content/influxdb/v2.2/query-data/flux/exists.md
+++ b/content/influxdb/v2.2/query-data/flux/exists.md
@@ -3,8 +3,8 @@ title: Check if a value exists
 seotitle: Use Flux to check if a value exists
 list_title: Exists
 description: >
-  Use the Flux `exists` operator to check if a record contains a key or if that
-  key's value is `null`.
+  Use the `exists` operator to check if a row record contains a column or if a
+  column's value is _null_.
 influxdb/v2.2/tags: [exists]
 menu:
   influxdb_2_2:
@@ -24,31 +24,26 @@ list_code_example: |
   ```
 ---
 
-Use the Flux `exists` operator to check if a record contains a key or if that
-key's value is `null`.
+Use the `exists` operator to check if a row record contains a column or if a
+column's value is _null_.
 
 ```js
-p = {firstName: "John", lastName: "Doe", age: 42}
-
-exists p.firstName
-// Returns true
-
-exists p.height
-// Returns false
+(r) => exists r.column
 ```
 
 If you're just getting started with Flux queries, check out the following:
 
 - [Get started with Flux](/{{< latest "flux" >}}/get-started/) for a conceptual overview of Flux and parts of a Flux query.
-- [Execute queries](/influxdb/v2.2/query-data/execute-queries/) to discover a variety of ways to run your queries.
+- [Execute queries](/influxdb/v2.4/query-data/execute-queries/) to discover a variety of ways to run your queries.
 
 Use `exists` with row functions (
 [`filter()`](/{{< latest "flux" >}}/stdlib/universe/filter/),
 [`map()`](/{{< latest "flux" >}}/stdlib/universe/map/),
 [`reduce()`](/{{< latest "flux" >}}/stdlib/universe/reduce/))
-to check if a row includes a column or if the value for that column is `null`.
+to check if a row includes a column or if the value for that column is _null_.
 
 #### Filter null values
+
 ```js
 from(bucket: "example-bucket")
     |> range(start: -5m)
@@ -56,6 +51,7 @@ from(bucket: "example-bucket")
 ```
 
 #### Map values based on existence
+
 ```js
 from(bucket: "default")
     |> range(start: -30s)
@@ -70,6 +66,7 @@ from(bucket: "default")
 ```
 
 #### Ignore null values in a custom aggregate function
+
 ```js
 customSumProduct = (tables=<-) => tables
     |> reduce(
@@ -86,3 +83,28 @@ customSumProduct = (tables=<-) => tables
         }),
     )
 ```
+
+#### Check if a statically defined record contains a key
+
+When you use the [record literal syntax](/flux/v0.x/data-types/composite/record/#record-syntax)
+to statically define a record, Flux knows the record type and what keys to expect.
+
+- If the key exists in the static record, `exists` returns `true`.
+- If the key does not exist in the static record, because the record type is
+  statically known, `exists` returns an error.
+
+```js
+import "internal/debug"
+
+p = {
+    firstName: "John",
+    lastName: "Doe",
+    age: 42,
+}
+
+exists p.firstName
+// Returns true
+
+exists p.height
+// Returns "error: record is missing label height"
+```
diff --git a/content/influxdb/v2.3/query-data/flux/exists.md b/content/influxdb/v2.3/query-data/flux/exists.md
index e2dc3e2ba..2701bb9df 100644
--- a/content/influxdb/v2.3/query-data/flux/exists.md
+++ b/content/influxdb/v2.3/query-data/flux/exists.md
@@ -3,8 +3,8 @@ title: Check if a value exists
 seotitle: Use Flux to check if a value exists
 list_title: Exists
 description: >
-  Use the Flux `exists` operator to check if a record contains a key or if that
-  key's value is `null`.
+  Use the `exists` operator to check if a row record contains a column or if a
+  column's value is _null_.
 influxdb/v2.3/tags: [exists]
 menu:
   influxdb_2_3:
@@ -24,31 +24,26 @@ list_code_example: |
   ```
 ---
 
-Use the Flux `exists` operator to check if a record contains a key or if that
-key's value is `null`.
+Use the `exists` operator to check if a row record contains a column or if a
+column's value is _null_.
 
 ```js
-p = {firstName: "John", lastName: "Doe", age: 42}
-
-exists p.firstName
-// Returns true
-
-exists p.height
-// Returns false
+(r) => exists r.column
 ```
 
 If you're just getting started with Flux queries, check out the following:
 
 - [Get started with Flux](/{{< latest "flux" >}}/get-started/) for a conceptual overview of Flux and parts of a Flux query.
-- [Execute queries](/influxdb/v2.3/query-data/execute-queries/) to discover a variety of ways to run your queries.
+- [Execute queries](/influxdb/v2.4/query-data/execute-queries/) to discover a variety of ways to run your queries.
 
 Use `exists` with row functions (
 [`filter()`](/{{< latest "flux" >}}/stdlib/universe/filter/),
 [`map()`](/{{< latest "flux" >}}/stdlib/universe/map/),
 [`reduce()`](/{{< latest "flux" >}}/stdlib/universe/reduce/))
-to check if a row includes a column or if the value for that column is `null`.
+to check if a row includes a column or if the value for that column is _null_.
 
 #### Filter null values
+
 ```js
 from(bucket: "example-bucket")
     |> range(start: -5m)
@@ -56,6 +51,7 @@ from(bucket: "example-bucket")
 ```
 
 #### Map values based on existence
+
 ```js
 from(bucket: "default")
     |> range(start: -30s)
@@ -70,6 +66,7 @@ from(bucket: "default")
 ```
 
 #### Ignore null values in a custom aggregate function
+
 ```js
 customSumProduct = (tables=<-) => tables
     |> reduce(
@@ -86,3 +83,28 @@ customSumProduct = (tables=<-) => tables
         }),
     )
 ```
+
+#### Check if a statically defined record contains a key
+
+When you use the [record literal syntax](/flux/v0.x/data-types/composite/record/#record-syntax)
+to statically define a record, Flux knows the record type and what keys to expect.
+
+- If the key exists in the static record, `exists` returns `true`.
+- If the key does not exist in the static record, because the record type is
+  statically known, `exists` returns an error.
+
+```js
+import "internal/debug"
+
+p = {
+    firstName: "John",
+    lastName: "Doe",
+    age: 42,
+}
+
+exists p.firstName
+// Returns true
+
+exists p.height
+// Returns "error: record is missing label height"
+```
diff --git a/content/influxdb/v2.4/query-data/flux/exists.md b/content/influxdb/v2.4/query-data/flux/exists.md
index b508dec17..7056ca9cf 100644
--- a/content/influxdb/v2.4/query-data/flux/exists.md
+++ b/content/influxdb/v2.4/query-data/flux/exists.md
@@ -3,8 +3,8 @@ title: Check if a value exists
 seotitle: Use Flux to check if a value exists
 list_title: Exists
 description: >
-  Use the Flux `exists` operator to check if a record contains a key or if that
-  key's value is `null`.
+  Use the Flux `exists` operator to check if a row record contains a column or if
+  that column's value is `null`.
 influxdb/v2.4/tags: [exists]
 menu:
   influxdb_2_4:
@@ -24,17 +24,11 @@ list_code_example: |
   ```
 ---
 
-Use the Flux `exists` operator to check if a record contains a key or if that
-key's value is `null`.
+Use the `exists` operator to check if a row record contains a column or if a
+column's value is _null_.
 
 ```js
-p = {firstName: "John", lastName: "Doe", age: 42}
-
-exists p.firstName
-// Returns true
-
-exists p.height
-// Returns false
+(r) => exists r.column
 ```
 
 If you're just getting started with Flux queries, check out the following:
@@ -46,9 +40,10 @@ Use `exists` with row functions (
 [`filter()`](/{{< latest "flux" >}}/stdlib/universe/filter/),
 [`map()`](/{{< latest "flux" >}}/stdlib/universe/map/),
 [`reduce()`](/{{< latest "flux" >}}/stdlib/universe/reduce/))
-to check if a row includes a column or if the value for that column is `null`.
+to check if a row includes a column or if the value for that column is _null_.
 
 #### Filter null values
+
 ```js
 from(bucket: "example-bucket")
     |> range(start: -5m)
@@ -56,6 +51,7 @@ from(bucket: "example-bucket")
 ```
 
 #### Map values based on existence
+
 ```js
 from(bucket: "default")
     |> range(start: -30s)
@@ -70,6 +66,7 @@ from(bucket: "default")
 ```
 
 #### Ignore null values in a custom aggregate function
+
 ```js
 customSumProduct = (tables=<-) => tables
     |> reduce(
@@ -86,3 +83,33 @@ customSumProduct = (tables=<-) => tables
         }),
     )
 ```
+
+#### Check if a statically defined record contains a key
+
+When you use the [record literal syntax](/flux/v0.x/data-types/composite/record/#record-syntax)
+to statically define a record, Flux knows the record type and what keys to expect.
+
+- If the key exists in the static record, `exists` returns `true`.
+- If the key exists in the static record, but has a _null_ value, `exists` returns `false`.
+- If the key does not exist in the static record, because the record type is
+  statically known, `exists` returns an error.
+
+```js
+import "internal/debug"
+
+p = {
+    firstName: "John",
+    lastName: "Doe",
+    age: 42,
+    height: debug.null(type: "int"),
+}
+
+exists p.firstName
+// Returns true
+
+exists p.height
+// Returns false
+
+exists p.hairColor
+// Returns "error: record is missing label hairColor"
+```