How to fix ERROR 1074: Column length too big in MySQL

First, understand what character set your database or table uses and how many bytes each character requires. Run:

SHOW CREATE TABLE your_table_name\G

Look for the CHARSET definition. Common character sets:
- latin1/iso-8859-1: 1 byte per character → max 65,535 character limit
- utf8mb3: 3 bytes per character → max 21,845 character limit (65,535 ÷ 3)
- utf8mb4: 4 bytes per character → max 16,383 character limit (65,535 ÷ 4)
- GBK: 2 bytes per character → max 32,767 character limit (65,535 ÷ 2)

The simplest fix is to reduce the declared size of your VARCHAR column to stay within limits. For UTF-8 databases, use VARCHAR(21845) or less:

-- Wrong (fails with Error 1074 on UTF-8)
CREATE TABLE users (
  description VARCHAR(65535)
);

-- Correct (respects the 65,535 byte limit for UTF-8)
CREATE TABLE users (
  description VARCHAR(21845)
);

-- Or use TEXT for unlimited length
CREATE TABLE users (
  description TEXT
);

For existing tables, use ALTER TABLE:

ALTER TABLE users MODIFY COLUMN description VARCHAR(21845);

If you need to store more than your VARCHAR limit allows, use TEXT data types:

-- For content up to 65,535 bytes
CREATE TABLE articles (
  content TEXT
);

-- For content up to 16MB
CREATE TABLE documents (
  content MEDIUMTEXT
);

-- For content up to 4GB
CREATE TABLE archives (
  content LONGTEXT
);

TEXT types don't count toward the 65,535 byte row limit and can store much larger content. However, they're slightly slower to index and query compared to VARCHAR.

Remember that the 65,535 byte limit is shared across ALL columns in a row, not per column. If you have multiple large VARCHAR columns, they sum together:

-- This may fail if total > 65,535 bytes
CREATE TABLE products (
  name VARCHAR(10000),
  description VARCHAR(10000),
  details VARCHAR(10000),
  notes VARCHAR(10000),
  comments VARCHAR(10000)
);
-- Total: 50,000 bytes - OK

-- This will fail
CREATE TABLE products (
  name VARCHAR(20000),
  description VARCHAR(20000),
  details VARCHAR(20000),
  notes VARCHAR(20000),
  comments VARCHAR(20000)
);
-- Total: 100,000 bytes - EXCEEDS LIMIT

To fix: either reduce individual VARCHAR sizes or move some columns to a separate table (normalization).

As a last resort, you can change your database or table to use a single-byte character set like Latin1, which allows VARCHAR(65535). However, this is rarely recommended because:

1. You lose support for Unicode characters
2. Modern applications expect UTF-8 support
3. It may break existing client code

If you must do this:

-- Change entire table to Latin1
ALTER TABLE users CONVERT TO CHARACTER SET latin1 COLLATE latin1_swedish_ci;

-- Or for a specific column
ALTER TABLE users MODIFY COLUMN description VARCHAR(65535) CHARACTER SET latin1;

Only use this approach if you're certain you don't need Unicode support.