Data Type Conversion

Certain data types in the database support implicit data type conversions, such as assignments and parameters called by functions. For other data types (for example, INT and composite types), you can use the type conversion functions provided by GaussDB, such as the CAST function, to forcibly convert them.

Table 1 lists common implicit data type conversions in GaussDB.

The valid value range of DATE supported by GaussDB is from 4713 BC to 294276 AD.

**Table 1** Implicit data type conversions
Raw Data Type	Target Data Type	Remarks
CHAR	VARCHAR2	-
CHAR	NUMBER	Raw data must consist of digits.
CHAR	DATE	Raw data cannot exceed the valid date range.
CHAR	RAW	-
CHAR	CLOB	-
VARCHAR2	CHAR	-
VARCHAR2	NUMBER	Raw data must consist of digits.
VARCHAR2	DATE	Raw data cannot exceed the valid date range.
VARCHAR2	CLOB	-
NUMBER	CHAR	-
NUMBER	VARCHAR2	-
DATE	CHAR	-
DATE	VARCHAR2	-
RAW	CHAR	-
RAW	VARCHAR2	-
CLOB	CHAR	-
CLOB	VARCHAR2	-
CLOB	NUMBER	Raw data must consist of digits.
INT4	CHAR	-
INT4	BOOLEAN	-
BOOLEAN	INT4	-