Oracle trunc function ___ static function

1.TRUNC (for dates)
The date value that the Trunc function truncates for the specified element.
Its specific syntax format is as follows:
TRUNC (Date[,fmt])

which

Date value FMT date format, which is truncated by the specified element format. Ignoring it is truncated by the nearest date.

The following is the use of this function: Trunc (sysdate, ' yyyy ')--2011-1-1 back to the first day of the year.
Trunc (sysdate, ' mm ')--2011-7-1 returns the first day of the month.

Trunc (sysdate, ' d ')--2011-7-10 returns to the first day of the current week.

Trunc (sysdate + 1) + 4/24--2011-7-14 4:00:00 returns one day after 4 o'clock in the morning.

2.TRUNC (for number)
The TRUNC function returns the processed value, which works very much like the round function, except that the function does not round the specified decimal number before or after the appropriate rounding selection.
Its specific syntax format is as follows
TRUNC (Number[,decimals])
which
Number to be intercepted
Decimals indicates the number of digits that need to be retained after the decimal point. Optional, ignore it to intercept all the decimal parts

The following is the use of this function:

TRUNC (89.985,2) =89.98
TRUNC (89.985) =89
TRUNC (89.985,-1) =80

Note: The second argument can be a negative number, represented as a portion of the following part of the specified digit to the left of the decimal point, that is, 0. Note: If you want to round up the interception, use round (number, decimal digits)