How to fix ERROR 1054: Unknown column in MySQL

DESCRIBE your_table_name;
-- or
SHOW COLUMNS FROM your_table_name;

-- If your table has column: user_id
-- This will fail:
SELECT userid FROM users;  -- ERROR 1054

-- This will work:
SELECT user_id FROM users;  -- OK

-- Wrong - MySQL thinks 'John' is a column:
INSERT INTO users (name, email) VALUES (John, [email protected]);
-- ERROR 1054: Unknown column 'John' in 'field list'

-- Correct - values are properly quoted:
INSERT INTO users (name, email) VALUES ('John', '[email protected]');

-- Wrong in WHERE clause:
SELECT * FROM users WHERE name = John;

-- Correct in WHERE clause:
SELECT * FROM users WHERE name = 'John';

-- Wrong - MySQL keyword without escaping:
SELECT order, group FROM my_table;
-- ERROR 1054 or syntax error

-- Correct - keywords escaped with backticks:
SELECT `order`, `group` FROM my_table;

-- Wrong - referencing original column name:
SELECT id AS user_id, name FROM users
UNION
SELECT id, name FROM customers
ORDER BY id;  -- ERROR 1054: Unknown column 'id'

-- Correct - using the alias from first SELECT:
SELECT id AS user_id, name FROM users
UNION
SELECT id, name FROM customers
ORDER BY user_id;

-- Wrong - using alias before it's available:
SELECT u.* FROM users AS u
JOIN posts AS p ON u.id = user_id;  -- ERROR 1054

-- Correct - using full table reference:
SELECT u.* FROM users AS u
JOIN posts AS p ON u.id = p.user_id;

-- Check current database:
SELECT DATABASE();

-- Switch to correct database:
USE correct_database_name;

-- Copy-paste the exact column name from DESCRIBE output
-- Or view raw bytes if needed (for hex values):
SHOW CREATE TABLE your_table_name\G

-- Recreate the column if it has encoding issues
ALTER TABLE your_table_name 
CHANGE COLUMN `old_name` `new_name` VARCHAR(255) CHARACTER SET utf8mb4 COLLATE utf8mb4_unicode_ci;