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How to calculate:
Click on the ‘Expressions’ tab Expressions tab within Query Manager to see the page below: the expression type is number; the length of the field is 2 for a ‘year’ calculation; in the Expression Text enter parenthesis, today’s date (SYSDATE), minus (-), the date field (i.e., date of birth), close parenthesis, slash (/) and the number 365.
Save the expression and ‘use use as field’ for field for the value to appear in your report.
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| substr (NATIONAL_ID, 6, 4) |
How to calculate:
In the '*Expression Type:' field field, select character. In the length field, enter 4. In the 'Expression Text', enter the phase mentioned above.
This selects four bytes of the NATIONAL_ID, starting in column 6. You may type in the field name (don't forget the prefix) or press the 'Add Field' link link to search for the field. Press 'OK' when when you are done.
Note Remember to use the field/expression in your report.
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Decode
What Expression Does:
This allows the query to convert a database value to something more meaningful. For instance, if the query needs to display the class schedule with days of the weeks rather than a 'Y' or 'N' flags.
The following images illustrated calculation of date using Expression:
Expression:
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| decode (E.MON, 'Y', 'Mo') || decode (E.TUES, 'Y', 'Tu') || decode (E.WED, 'Y', 'We') || decode (E.THURS, 'Y', 'Th') || decode (E.FRI, 'Y', 'Fr') || decode (E.SAT, 'Y', 'Sa') || decode (E.SUN, 'Y', 'Su') |
How to calculate:
In the Expression Type: field, select character. In the length field, enter 14, to allow two bytes for each day of the week (7 x 2). In the Expression Text, enter the phase mentioned above
This converts the 'Y' value into a day of the week. The 'N' value is ignored. The '||' (double bar) is the concatenate symbol. You may type in the field name (don't forget the prefix) or press the 'Add Field' link link to search for the field. Press OK when you are done.
Note Remember to use the field/expression in your report. So instead of seven columns with 'Y' or 'N', the query will print something like 'MoWeFr'.