EC
1166
MySQLERRORCommonDDLHIGH confidence

Incorrect column name

Production Risk

Low — DDL fails; no data loss.

What this means

ER_WRONG_COLUMN_NAME (1166, SQLSTATE 42000) is raised when a column name contains invalid characters or is otherwise syntactically incorrect.

Why it happens
  1. 1Column name contains a null byte or other control character
  2. 2Column name is empty
  3. 3Column name exceeds 64 characters
How to reproduce
trigger — this will error
trigger — this will error
CREATE TABLE t (`col name` INT);

expected output

ERROR 1166 (42000): Incorrect column name 'col name'

Fix

Use valid identifier characters in column names

WHEN Always.

Use valid identifier characters in column names
CREATE TABLE t (col_name INT);

Why this works

Column names should use letters, digits, and underscores; spaces require backtick quoting and are generally discouraged.

What not to do

✕ Use column names with spaces even when backtick-quoted

While technically valid with quoting, space-containing names require consistent quoting everywhere they are referenced, creating maintenance burden.

Sources
Official documentation ↗

MySQL 8.0 — 1166 ER_WRONG_COLUMN_NAME

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