MySQL Error 1048

Error number

1048

SQLSTATE

23000

Symbol

ER_BAD_NULL_ERROR

Product

MySQL Server

Versions

MySQL 5.7, 8.0 and 8.4

Category

Keys & Constraints

Last reviewed

24 October 2026

What it means

Error 1048 means an INSERT or UPDATE explicitly put NULL into a column declared NOT NULL, so MySQL rejected the statement.

A NOT NULL column must always hold a value. When a statement supplies NULL for it, either as a literal, a bound parameter that is null, or a NULL coming out of a SELECT or a LEFT JOIN, MySQL returns 1048 and names the column. A DEFAULT on the column does not help: the default is used only when the column is left out of the INSERT or given the DEFAULT keyword, not when NULL is sent explicitly. That is why created_at DATETIME NOT NULL DEFAULT CURRENT_TIMESTAMP still fails when the application passes NULL.

Leaving a NOT NULL column without a default out of the INSERT is a different error, 1364. Under strict mode (the MySQL 8.0 default) 1048 is always an error. Without strict mode a single-row INSERT still fails, but a multi-row INSERT, INSERT ... SELECT or UPDATE only warns and stores the type's implicit default (an empty string, 0 or a zero date), which silently corrupts data. Changing an existing column to NOT NULL while it holds NULLs gives error 1138 instead.

Common causes

• A form field or API value is missing, so the application binds NULL to a required column.
• The application sends NULL for a column that has a DEFAULT, expecting the default to apply (it does not).
• An INSERT ... SELECT or import copies NULLs from a staging table or a source column that allows them.
• An UPDATE with a LEFT JOIN or a subquery sets the column from a row that was not found, which yields NULL.
• An ORM maps an unset property to NULL and includes every column in the INSERT.

Diagnose it

Read-only These statements only read metadata (information_schema, performance_schema and SHOW statements) or your own data. They do not change data, privileges or configuration, so they are safe to run first.

SELECT column_name, is_nullable, column_default, extra
FROM information_schema.columns
WHERE table_schema = DATABASE()
  AND table_name = 'customers'
ORDER BY ordinal_position;

SELECT name, email
FROM staging_customers
WHERE name IS NULL OR email IS NULL;

SELECT @@SESSION.sql_mode, @@GLOBAL.sql_mode;

How to fix it

Each fix is labelled with what it changes. Try read-only checks and the least invasive fix first, and test changes outside production.

INSERT INTO customers (name, email, created_at)
VALUES ('Ali', 'ali@example.com', DEFAULT);

INSERT INTO customers (name, email)
SELECT name, COALESCE(email, CONCAT('unknown+', name, '@example.com'))
FROM staging_customers
WHERE name IS NOT NULL;

ALTER TABLE customers MODIFY email VARCHAR(200) NULL;

Examples

Inserting NULL into a NOT NULL column

CREATE TABLE customers (
    id    INT AUTO_INCREMENT PRIMARY KEY,
    name  VARCHAR(100) NOT NULL,
    email VARCHAR(200) NOT NULL
);

INSERT INTO customers (name, email) VALUES (NULL, 'sara@example.com');

ERROR 1048 (23000): Column 'name' cannot be null

Sending NULL to a column that has a DEFAULT

CREATE TABLE customers (
    id         INT AUTO_INCREMENT PRIMARY KEY,
    name       VARCHAR(100) NOT NULL,
    created_at DATETIME NOT NULL DEFAULT CURRENT_TIMESTAMP
);

INSERT INTO customers (name, created_at) VALUES ('Ali', NULL);  -- the default is not used for an explicit NULL

ERROR 1048 (23000): Column 'created_at' cannot be null

INSERT ... SELECT from a staging table that contains NULLs

CREATE TABLE customers (
    id    INT AUTO_INCREMENT PRIMARY KEY,
    name  VARCHAR(100) NOT NULL,
    email VARCHAR(200) NOT NULL
);
CREATE TABLE staging_customers (name VARCHAR(100), email VARCHAR(200));
INSERT INTO staging_customers VALUES ('Omar', 'omar@example.com'), ('Lina', NULL);

INSERT INTO customers (name, email)
SELECT name, email FROM staging_customers;

ERROR 1048 (23000): Column 'email' cannot be null

An UPDATE through a LEFT JOIN that finds no match

CREATE TABLE customers (
    id    INT PRIMARY KEY,
    name  VARCHAR(100) NOT NULL,
    email VARCHAR(200) NOT NULL
);
CREATE TABLE email_updates (customer_id INT, new_email VARCHAR(200));
INSERT INTO customers VALUES (1, 'Sara', 'sara@example.com'), (2, 'Ali', 'ali@example.com');
INSERT INTO email_updates VALUES (1, 'sara@new.example.com');

UPDATE customers AS c
LEFT JOIN email_updates AS u ON u.customer_id = c.id
SET c.email = u.new_email;  -- customer 2 has no update, so u.new_email is NULL

ERROR 1048 (23000): Column 'email' cannot be null

How to prevent it

Validate required values in the application and treat 1048 as a validation error, not a crash. Never send NULL for a column you want defaulted: omit it or use DEFAULT. In UPDATE statements, join with INNER JOIN (or add a WHERE clause) so rows without a match are not touched.

Keep strict mode on. Without it, multi-row inserts and updates replace NULL with empty strings, zeros or zero dates and only raise a warning, which is much harder to clean up later than an error you fix today.

Common questions

Learn more on CodeWithSQL

• SQL NULL values explained
• SQL constraints explained

Official documentation

• MySQL 8.0 server error message reference
• Data type default values
• Server SQL modes (strict mode)
• Problems with NULL values

Last technically reviewed 24 October 2026; examples and diagnostics run on MySQL 8.0.46. Message templates checked against the server's error catalogue (perror) for that version.