SQL in a Nutshell, 2nd Edition

Name

DB2

Synopsis

DB2 supports the SQL2003 built-in scalar functions CURRENT_DATE, CURRENT_TIME, CURRENT_TIMESTAMP, CURRENT_USER, and USER. The SQL2003 scalar functions CURRENT_ROLE, LOCAL_TIME, LOCAL_TIMESTAMP, SESSION_USER, and SYSTEM_USER are not supported.

MySQL

MySQL supports all the SQL2003 built-in scalar functions, plus Oracle’s variant SYSDATE. In addition, MySQL supports NOW( ) as a synonym of the function CURRENT_TIMESTAMP.

Oracle

Oracle supports USER and SYSDATE as a synonym of CURRENT_TIMESTAMP.

PostgreSQL

PostgreSQL supports all the SQL2003 built-in scalar functions except SESSION_USER.

SQL Server

SQL Server supports all the built-in scalar functions.

Examples

The following queries retrieve the values from built-in functions. Notice that the various platforms return dates in their native formats:

/* On MySQL */
SELECT CURRENT_TIMESTAMP;'2001-12-15 23:50:26'
/* DB2 */
VALUES CURRENT_TIMESTAMP'2001-12-15 23.50.26.000000'
/* On Microsoft SQL Server */
SELECT CURRENT_TIMESTAMPGO'Dec 15,2001 23:50:26'
/* On Oracle */
SELECT USER FROM dual;dylan