diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index d9aa7c96072..37cb424df51 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -11855,14 +11855,28 @@ table2-mapping
- In json_populate_record>, json_populate_recordset>,
- json_to_record> and json_to_recordset>,
- type coercion from the JSON is best effort> and may not result
- in desired values for some types. JSON keys are matched to
- identical column names in the target row type. JSON fields that do not
- appear in the target row type will be omitted from the output, and
- target columns that do not match any JSON field will simply be NULL.
+ While the examples for the functions
+ json_populate_record,
+ json_populate_recordset,
+ json_to_record and
+ json_to_recordset use constants, the typical use
+ would be to reference a table in the FROM clause
+ and use one of its json or jsonb columns
+ as an argument to the function. Extracted key values can then be
+ referenced in other parts of the query, like WHERE
+ clauses and target lists. Extracting multiple values in this
+ way can improve performance over extracting them separately with
+ per-key operators.
+
+
+ JSON keys are matched to identical column names in the target
+ row type. JSON type coercion for these functions is best
+ effort
and may not result in desired values for some types.
+ JSON fields that do not appear in the target row type will be
+ omitted from the output, and target columns that do not match any
+ JSON field will simply be NULL.
+