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Calendar Date/Time Functions
The calendar date/time functions manipulate data of the data types DATE and DATETIME.
Current_Date
Returns the current date. The date is determined by the system in which the Siebel Analytics Server is running.
Syntax:
CURRENT_DATE
Current_Time
Returns the current time. The time is determined by the system in which the Siebel Analytics Server is running.
Syntax:
CURRENT_TIME (n)
where:
Current_TimeStamp
Returns the current date/timestamp. The timestamp is determined by the system in which the Siebel Analytics Server is running.
Syntax:
CURRENT_TIMESTAMP (n)
where:
Day_Of_Quarter
Returns a number (between 1 and 92) corresponding to the day of the quarter for the specified date.
Syntax:
DAY_OF_QUARTER (date_expression)
where:
DayName
Returns the day of the week for a specified date.
Syntax:
DAYNAME (date_expression)
where:
DayOfMonth
Returns the number corresponding to the day of the month for a specified date.
Syntax:
DAYOFMONTH (date_expression)
where:
DayOfWeek
Returns a number between 1 and 7 corresponding to the day of the week, Sunday through Saturday, for a specified date. For example, the number 1 corresponds to Sunday, and the number 7 corresponds to Saturday.
Syntax:
DAYOFWEEK (date_expression)
where:
DayOfYear
Returns the number (between 1 and 366) corresponding to the day of the year for a specified date.
Syntax:
DAYOFYEAR (date_expression)
where:
Hour
Returns a number (between 0 and 23) corresponding to the hour for a specified time. For example, 0 corresponds to 12 a.m. and 23 corresponds to 11 p.m.
Syntax:
HOUR (time_expression)
where:
Minute
Returns a number (between 0 and 59) corresponding to the minute for a specified time.
Syntax:
MINUTE (time_expression)
where:
Month
Returns the number (between 1 and 12) corresponding to the month for a specified date.
Syntax:
MONTH (date_expression)
where:
Month_Of_Quarter
Returns the number (between 1 and 3) corresponding to the month in the quarter for a specified date.
Syntax:
MONTH_OF_QUARTER (date_expression)
where:
MonthName
Returns the name of the month for a specified date.
Syntax:
MONTHNAME (date_expression)
where:
Now
Returns the current timestamp. The NOW function is equivalent to the CURRENT_TIMESTAMP function.
Syntax:
NOW ()
Quarter_Of_Year
Returns the number (between 1 and 4) corresponding to the quarter of the year for a specified date.
Syntax:
QUARTER_OF_YEAR (date_expression)
where:
Second
Returns the number (between 0 and 59) corresponding to the seconds for a specified time.
Syntax:
SECOND (time_expression)
where:
TimestampAdd
The TimestampAdd function adds a specified number of intervals to a specified timestamp. A single timestamp is returned.
Syntax:
TimestampAdd (interval, integer-expression, timestamp-expression)
where:
A null integer-expression or a null timestamp-expression passed to this function will result in a null return value.
In the simplest scenario, this function merely adds the specified integer value (integer-expression) to the appropriate component of the timestamp, based on the interval. Adding a week translates to adding seven days, and adding a quarter translates to adding three months. A negative integer value results in a subtraction (going back in time).
An overflow of the specified component (such as more than 60 seconds, 24 hours, twelve months, and so on) necessitates adding an appropriate amount to the next component. For example, when adding to the day component of a timestamp, this function considers overflow and takes into account the number of days in a particular month (including leap years when February has 29 days).
When adding to the month component of a timestamp, this function verifies that the resulting timestamp has a sufficient number of days for the day component. For example, blindly adding 1 month to `2000-05-31' results not in `2000-06-31' because June does not have 31 days. This function reduces the day component to the last day of the month—`2000-06-30' in this example.
A similar issue arises when adding to the year component of a timestamp having a month component of February and a day component of 29 (that is, last day of February in a leap year). If the resulting timestamp does not fall on a leap year, the function reduces the day component to 28.
These actions conform to the behavior of Microsoft's SQL Server and Oracle's native OCI interface.
The following queries are examples of the TimestampAdd function and its results:
The following query asks for the resulting timestamp when 3 days are added to `2000-02-27 14:30:00'. Since February, 2000 is a leap year, the query returns a single timestamp of `2000-03-01 14:30:00'.
Select TimestampAdd(SQL_TSI_DAY, 3,
TIMESTAMP`2000-02-27 14:30:00')
From Employee where employeeid = 2;
The following query asks for the resulting timestamp when 7 months are added to `1999-07-31 0:0:0'. The query returns a single timestamp of `2000-02-29 00:00:00'. Notice the reduction of day component to 29 because of the shorter month of February.
Select TimestampAdd(SQL_TSI_MONTH, 7,
TIMESTAMP`1999-07-31 00:00:00')
From Employee where employeeid = 2;
The following query asks for the resulting timestamp when 25 minutes are added to `2000-07-31 23:35:00'. The query returns a single timestamp of `2000-08-01 00:00:00'. Notice the propagation of overflow through the month component.
Select TimestampAdd(SQL_TSI_MINUTE, 25,
TIMESTAMP`2000-07-31 23:35:00')
From Employee where employeeid = 2;
TimeStampDiff
The TimestampDiff function returns the total number of specified intervals between two timestamps.
Syntax:
TimestampDiff (interval, timestamp-expression1, timestamp-expression2)
where:
A null timestamp-expression parameter passed to this function will result in a null return value.
This function first determines the timestamp component that corresponds to the specified interval parameter. For example, SQL_TSI_DAY corresponds to the day component and SQL_TSI_MONTH corresponds to the month component.
The function then looks at the higher order components of both timestamps to calculate the total number of intervals for each timestamp. For example, if the specified interval corresponds to the month component, the function calculates the total number of months for each timestamp by adding the month component and twelve times the year component.
Finally, the function subtracts the first timestamp's total number of intervals from the second timestamp's total number of intervals.
The TimestampDiff function rounds up to the next integer whenever fractional intervals represent a crossing of an interval boundary. For example, the difference in years between `1999-12-31' and `2000-01-01' is one year because the fractional year represents a crossing from one year to the next (that is, 1999 to 2000). By contrast, the difference between `1999-01-01' and `1999-12-31' is zero years because the fractional interval falls entirely within a particular year (that is, 1999).
Microsoft's SQL Server exhibits the same rounding behavior; IBM's DB2 does not—it always rounds down. Oracle does not implement a generalized timestamp difference function.
When calculating the difference in weeks, the function calculates the difference in days and divides by seven before rounding. Additionally, the function takes into account how the Siebel Analytics Server administrator has configured the start of a new week in the NQSConfig.INI file using the parameter FIRST_DAY_OF_THE_WEEK (which defaults to Sunday).
For example, with Sunday as the start of the week, the difference in weeks between `2000-07-06' (a Thursday) and `2000-07-10' (the following Monday) results in a value of one week. With Tuesday as the start of the week, however, the function would return zero weeks since the fractional interval falls entirely within a particular week.
When calculating the difference in quarters, the function calculates the difference in months and divides by three before rounding.
IBM's DB2 provides a generalized timestamp difference function (TIMESTAMPDIFF) but it simplifies the calculation by always assuming a 365-day year, 52-week year, and 30-day month.
The following is an example of the TimestampDiff function and its results:
The following query asks for a difference in days between timestamps `1998-07-31 23:35:00' and `2000-04-01 14:24:00'. It returns a value of 610. Notice that the leap year in 2000 results in an additional day.
Select TimestampDIFF(SQL_TSI_DAY, TIMESTAMP`1998-07-31 23:35:00', TIMESTAMP`2000-04-01 14:24:00') From Employee where employeeid = 2;
The Siebel Analytics Server pushes down the TIMESTAMPADD and TIMESTAMPDIFF functions to Microsoft's SQL Server and ODBC databases by default. While the Siebel Analytics Server can also push to IBM's DB2, the features table is turned off by default due to DB2's semantics. The features table is also turned off by default for Oracle, since Oracle databases do not fully support these functions.
Week_Of_Quarter
Returns a number (between 1 and 13) corresponding to the week of the quarter for the specified date.
Syntax:
WEEK_OF_QUARTER (date_expression)
where:
Week_Of_Year
Returns a number (between 1 and 53) corresponding to the week of the year for the specified date.
Syntax:
WEEK_OF_YEAR (date_expression)
where:
Year
Returns the year for the specified date.
Syntax:
YEAR (date_expression)
where:
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Siebel Analytics Server Administration Guide Published: 23 June 2003 |