函数表达式可从内建的 SQL 函数或从用户定义的函数返回一个或多个值,如下图所示。
EXTEND (call_dtime, YEAR TO SECOND)
HEX (LENGTH(123))
MDY (12, 7, 1900 + cur_yr)
TAN (radians)
DATE (365/2)
ABS (-32)
LENGTH ('abc') + LENGTH (pvar)
EXP (3)
HEX (customer_num)
MOD (10,3)