PostgreSQL throws sql_json_scalar_required (SQLSTATE 2203F) when a SQL/JSON path query tries to return an array or object where a scalar value is required.
sql_json_scalar_required (SQLSTATE 2203F) appears when a SQL/JSON query must return a single scalar but instead yields an array or object. Force the path to pick one scalar element or wrap the query in ->> to extract a text scalar to resolve the error.
PostgreSQL Error 2203F
PostgreSQL raises sql_json_scalar_required (error code 2203F) when a SQL/JSON path or JSON table expression must output a scalar value but encounters a JSON array or object instead.
The SQL/JSON specification distinguishes scalars (number, string, boolean, null) from non-scalar structures (arrays, objects). Functions such as JSON_VALUE and operators like ->> demand scalars.
Returning a non-scalar breaks the contract and triggers this error.
Fixing the issue is critical because downstream code often casts the scalar to a native SQL type.
If the query returns an array or object, implicit casts fail and data pipelines stop.
jsonb_path_query_first, JSON_VALUE, or the ->> operator select a path that points to an array or object instead of a single atomic element.
A wildcard or lax mode path unintentionally expands to multiple values, forcing PostgreSQL to choose between scalars and arrays, which violates the scalar requirement.
Explicit casting of a JSON column to a SQL type (e.g., ::int) without ensuring the extracted JSON piece is scalar also causes the same exception.
Rewrite the JSON path so it targets exactly one scalar element.
Use array subscripts [0], key names, or predicates to narrow the result.
If multiple values are expected, switch to JSON_QUERY or jsonb_path_query to legally return arrays or objects.
When you only need text, apply ->> or CAST after isolating one element.
Extracting the first email from a JSON array of addresses requires the subscripts operator: data -> 'emails' ->> 0.
Casting a JSON numeric string to integer works only if you first use ->> to return text: (data ->> 'age')::int.
Building JSON_TABLE rows demands scalar columns; wrap non-scalar columns in JSON_TABLE nested paths or flatten them beforehand.
Validate JSON structure with CHECK constraints that enforce scalar fields when you design tables.
Write JSON paths explicitly and avoid wildcards in production queries.
Prefer strict mode (ABSENT ON ERROR) to catch issues early.
Use Galaxy’s live result preview to verify that JSON_VALUE calls return scalar samples before committing queries.
2203E sql_json_array_not_found appears when a required array element is missing; apply ABSENT ON NULL to silence it.
2203B sql_json_item_missing fires when a key is absent; use the ? operator to check first.
22032 sql_json_sequence_not_scalar signals multiple scalar results; add predicates to narrow to one.
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Rows where the path points to arrays or objects break the scalar rule. Validate each row or use strict mode with DEFAULT.
Yes. Wrap the call in TRY or use the ABSENT ON NULL clause in JSON_VALUE to substitute NULL when the scalar rule fails.
No. SQL/JSON functions were added in v12. Earlier versions use jsonb operators that can still complain with similar messages.
Galaxy’s result preview shows the JSON sample inline, letting you confirm the output is scalar before executing in production.
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