MySQL raises ER_INVALID_TYPE_FOR_JSON (code 3146, SQLSTATE 22032) when a non-JSON data type is passed to a JSON function that expects a valid JSON string or JSON column.
ER_INVALID_TYPE_FOR_JSON occurs when a MySQL JSON function receives a non-JSON argument. Cast the value to JSON or supply a valid JSON string or JSON column to resolve the error.
ER_INVALID_TYPE_FOR_JSON
MySQL error 3146 appears when a JSON built-in such as JSON_EXTRACT, JSON_ARRAY, or JSON_MERGE receives an argument whose data type is not JSON or a properly formatted JSON string. Introduced in MySQL 5.7.8, the engine validates every argument and refuses incompatible types, returning SQLSTATE 22032.
Handling this error quickly is important because it stops the entire statement, blocks stored program execution, and can cascade into application failures. Understanding its root causes allows you to correct queries, redesign table schemas, and harden data pipelines.
The most common trigger is passing a plain text, numeric, or NULL column into a JSON function without explicit conversion. MySQL checks argument data types in left-to-right order and fails on the first mismatch.
The error also appears when you insert non-quoted JSON text into a JSON column, cast a non-JSON column to JSON incorrectly, or migrate legacy tables that store pseudo-JSON blobs as VARCHAR.
The quickest fix is to convert the offending argument with CAST(value AS JSON) or JSON_QUOTE(value). If the column should store structured data, alter its definition to JSON and update legacy rows.
When the input is dynamic, wrap JSON functions with IF(JSON_VALID(val), json_func(val), NULL) to prevent runtime failures. Always validate user-supplied strings in middleware before executing SQL.
Reading option lists from a varchar field: migrate the column to JSON to enable indexed searches. During migration, convert existing comma-separated text with JSON_ARRAYAGG or application code.
Aggregating values into an array: use JSON_ARRAY or GROUP_CONCAT combined with JSON_ARRAYAGG to build a valid JSON document instead of concatenating raw strings.
Always declare columns that store JSON data using the JSON data type. MySQL enforces validity and provides automatic checks.
Run unit tests that call JSON_VALID on inputs. Reject or sanitize data that fails validation. Use Galaxy’s AI copilot to scan queries for implicit JSON casts and suggest explicit conversions.
22032 can accompany ER_INVALID_JSON_TEXT if the supplied string is syntactically invalid. Fix by escaping quotes and ensuring proper brackets.
ER_DATA_TOO_LONG may fire when a JSON string exceeds column length in a VARCHAR field. Convert to JSON type or raise the limit.
Legacy tables often store pseudo-JSON text in VARCHAR columns. JSON_EXTRACT fails because the column type is not JSON.
Numbers, dates, and NULL are rejected unless wrapped in JSON_ARRAY or explicitly cast to JSON.
Using CAST(col AS CHAR) inside a JSON function strips JSON type information and triggers the error.
INSERT or UPDATE without quoting special characters creates a non-JSON payload that the engine refuses.
The supplied string is not valid JSON syntax even though the type is JSON.
The JSON document exceeds the target column length when stored in VARCHAR or TEXT fields.
The JSON path expression given to JSON_EXTRACT or JSON_SET is malformed.
MariaDB forks before 10.4 lack native JSON types, so the exact error code is absent. Similar validation errors may surface as generic syntax errors.
No. MySQL enforces JSON type validation at the storage engine layer, independent of SQL_MODE.
No. Casting to CHAR removes JSON typing. Use CAST(... AS JSON) or JSON_QUOTE instead.
Galaxy’s context-aware autocomplete flags type mismatches, and its AI copilot rewrites queries with proper JSON casts, reducing runtime errors.
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