<p>MySQL raises error 1485 when a partition definition specifies a subpartition count that conflicts with an earlier declaration in the same CREATE or ALTER TABLE statement.</p>
<p>MySQL Error 1485 ER_PARTITION_WRONG_NO_SUBPART_ERROR occurs when the number of SUBPARTITION clauses in one partition differs from the table’s earlier definition. Align every partition with the same subpartition count or drop subpartitioning to resolve the issue.</p>
Wrong number of subpartitions defined, mismatch with
MySQL throws error 1485 with condition name ER_PARTITION_WRONG_NO_SUBPART_ERROR when a CREATE TABLE or ALTER TABLE statement defines partitions that contain an inconsistent number of SUBPARTITION clauses.
The storage engine expects each partition in a subpartitioned table to share an identical subpartition structure. If one partition lists four subpartitions and another lists two, MySQL aborts the DDL and returns this error.
During query planning, the optimizer relies on a uniform subpartition map to prune partitions accurately. A mismatch breaks that assumption, leading to undefined behavior. MySQL therefore blocks the statement to maintain internal consistency.
The error usually appears while engineers experiment with composite partitioning, migrate legacy tables, or adjust subpartition counts during schema refactors.
The statement that triggers the error fails and no structural changes are applied. Reads and writes on the original table continue unaffected, but the intended partitioning strategy remains incomplete.
Galaxy’s SQL editor validates DDL before execution and highlights inconsistent SUBPARTITION clauses in real time, allowing developers to fix mismatches instantly and avoid downtime.
One PARTITION clause specifies SUBPARTITION 4 while another specifies SUBPARTITION 2, producing a mismatch.
Some partitions declare SUBPARTITION names explicitly while others rely on the default count inferred from PARTITIONS n.
An ALTER TABLE ADD PARTITION statement introduces a new partition with a subpartition count different from the original table definition.
Developers reuse DDL snippets from another table without updating all SUBPARTITION counts consistently.
Raised when subpartitioning is defined without a supporting partition type that allows it.
Occurs when a RANGE partition lacks a MAXVALUE catch-all partition.
Indicates that partition columns do not match primary key or unique index columns.
No. MySQL requires every partition to share the exact subpartition structure.
Error 1485 appears in MySQL 5.1 and later whenever subpartition counts mismatch.
Yes, but aligning SUBPARTITION counts is safer and avoids data reloads.
Galaxy flags inconsistent SUBPARTITION clauses during query composition and suggests corrections before execution.
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