Default values for table columns

The rules that apply to the default value for a column that you can specify with the DEFAULT clause of the CREATE TABLE or ALTER TABLE statement are more strict than those for entering values in table columns. The rules also apply for the definition of local variables (in routines). They are contained in the table below:

SQL data type of the column	Possible SQL default value
CHAR(length) VARCHAR(max)	Alphanumeric literal with length <= length or max Special literal ([CURRENT_ ]USER and SYSTEM_USER only (only recommended for length or max <= 128)) NULL
NCHAR(cu_length) NVARCHAR(cu_max	National literal with length >= cu_length or cu_max NULL
REF(table)	As for CHAR(237)
DECIMAL(precision,scale) NUMERIC(precision,scale) INTEGER SMALLINT	Fixed-point or floating-point number belonging to the range of values for the column NULL
REAL, DOUBLE PRECISION FLOAT(precision)	Numeric literal (the number is rounded off if necessary) NULL
DATE	Literal of the type DATE CURRENT_DATE NULL
TIME(3)	Literal of the type TIME(3) CURRENT_TIME NULL
TIMESTAMP(3)	Literal of the type TIMESTAMP(3) CURRENT_TIMESTAMP NULL

Table 12: Default values for table columns