<p>The error appears when a CREATE or ALTER TABLE statement specifies a number of partitions without explicitly defining each partition.</p>
<p>MySQL Error 1492 ER_PARTITIONS_MUST_BE_DEFINED_ERROR means you used PARTITION n but did not declare every partition. Define each partition (PARTITION p0 VALUES …) or drop the partition count to fix the problem.</p>
For %s partitions each partition must be defined
The server raises this error when a CREATE TABLE or ALTER TABLE command includes PARTITION BY ... PARTITIONS n but does not supply an explicit PARTITION clause for each partition.
MySQL expects a full description of every partition when the PARTITIONS keyword is used, covering partition names, value ranges or hashing, storage options, and tablespaces.
MySQL validates that the declared partition count matches the number of PARTITION definitions. When the count is greater than the definitions given, the validation fails and error 1492 is thrown.
The error is version-agnostic and appears in MySQL 5.7, 8.0, Percona, and MariaDB forks that retain the partitioning parser.
Add a PARTITION clause for each partition listed in the PARTITIONS keyword, or remove the PARTITIONS keyword and let MySQL infer the count from the supplied definitions.
Check generated SQL from ORMs or migration tools; many add PARTITIONS n automatically. Edit the migration to include explicit definitions or eliminate the count.
During range partitioning on a date column developers often write PARTITION BY RANGE(YEAR(order_date)) PARTITIONS 4 without then adding PARTITION p0, p1, p2, p3. Adding these clauses or dropping PARTITIONS 4 solves it.
When cloning an example from documentation, some snippets omit details for brevity. Copying those snippets directly into production will surface this error until all partitions are defined.
Always pair the PARTITIONS keyword with an equal number of PARTITION clauses. Treat the PARTITIONS keyword as a contract that must be fulfilled.
Peer-review schema migrations with Galaxy or a similar SQL editor to catch invalid partition syntax before running against production.
Error 1486 Wrong number of partitions is triggered when partition definitions exceed the declared count, the opposite of 1492. Align counts to fix.
Error 1503 A partition must be used with PRIMARY KEY occurs when the partitioning key does not include the primary key. Add the PK column to the partition key or drop partitioning.
Developer adds PARTITIONS n but forgets to list each partition definition.
ORM or migration framework inserts PARTITIONS automatically without definitions.
Example snippets omit full partition list for brevity, causing error in real execution.
During refactors, a teammate deletes some PARTITION lines but leaves the count unchanged.
Appears when the number of PARTITION clauses exceeds the PARTITIONS count.
Raised when partition key does not include all primary key columns.
Occurs when an unsupported column type is used in the partition key.
No. The rule is present in MySQL 5.7, 8.0, MariaDB, and Percona Server.
Only when you omit the PARTITIONS keyword. If you declare a count, you must define each partition manually.
Yes. Excessive partitions can slow query planning. Use only the number needed for maintenance and pruning.
Galaxy flags schema errors in real time and lets teams review migrations together, preventing invalid partition statements from reaching production.
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