EC
1490
MySQLERRORNotablePartitioningHIGH confidence

Wrong number of partitions — mismatch with previous setting

Production Risk

Low — DDL error; the table will not be created.

What this means

ER_PARTITION_WRONG_NO_PART_ERROR (1490, SQLSTATE HY000) is raised when the number of partition definitions does not match the PARTITIONS N count.

Why it happens
  1. 1PARTITIONS N specified but a different number of partition definitions provided
  2. 2Explicit partition count conflicts with the implied count from partition definitions
How to reproduce
trigger — this will error
trigger — this will error
CREATE TABLE t (id INT)
PARTITION BY HASH(id) PARTITIONS 4 (
  PARTITION p0,
  PARTITION p1
  -- Only 2 defined but PARTITIONS 4 specified
);

expected output

ERROR 1490 (HY000): Wrong number of partitions defined, mismatch with previous setting

Fix

Make the partition count and definitions consistent

Make the partition count and definitions consistent
-- Let MySQL handle partition naming automatically:
CREATE TABLE t (id INT)
PARTITION BY HASH(id) PARTITIONS 4;

-- Or define exactly the number you specified:
CREATE TABLE t (id INT)
PARTITION BY HASH(id) PARTITIONS 2 (
  PARTITION p0,
  PARTITION p1
);

Why this works

The PARTITIONS N count and the number of explicitly defined partitions must agree.

Sources
Official documentation ↗

MySQL 8.0 — 1490 ER_PARTITION_WRONG_NO_PART_ERROR

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