9.1.7 NULL Values
NULL value means “no data.”
NULL can be written in any lettercase. A synonym is
\N (case-sensitive). Treatment of
\N as a synonym for
NULL in SQL statements is deprecated as of MySQL 5.7.18 and is removed in MySQL 8.0; use
Be aware that the
NULL value is different from values such as
0 for numeric types or the empty string for string types. For more information, see Section B.4.4.3, “Problems with NULL Values”.
For text file import or export operations performed with
LOAD DATA or
SELECT ... INTO OUTFILE,
NULL is represented by the
\N sequence. See Section 13.2.6, “LOAD DATA Statement”. Use of
\N in text files is unaffected by the deprecation of
\N in SQL statements.
For sorting with
NULL values sort before other values for ascending sorts, after other values for descending sorts.