currenttimestamp

CURRENTTIMESTAMP (often written as CURRENT_TIMESTAMP) is a built-in function used in many database systems and programming environments to obtain the current date and time from the system clock. When evaluated, it returns a timestamp value that represents the moment of the call. The function is commonly provided by standards such as ANSI SQL and by many vendor-specific dialects.

Semantics and data type: The exact return type and time zone handling vary by system. In many SQL dialects the value is time zone aware or dependent on a session time zone setting, and the precision may include fractional seconds. Because the value is derived from the system clock, repeated evaluations can yield different results within the same statement.

Common uses: It is frequently used to timestamp records (for created_at or updated_at columns), to filter data by a time window, or as part of calculations that depend on the current date and time. It is often an alternative to functions like NOW(), SYSDATE, or GETDATE() depending on the environment.

Examples of variations by system: PostgreSQL supports CURRENT_TIMESTAMP and NOW() as equivalent; Oracle's CURRENT_TIMESTAMP returns TIMESTAMP WITH TIME ZONE; MySQL's CURRENT_TIMESTAMP returns a date and time value; SQL Server offers GETDATE() and SYSDATETIME(), while CURRENT_TIMESTAMP is an ANSI-standard synonym. Developers should consult the specific documentation for the exact semantics, particularly time zone behavior and precision.