Difference between revisions of "PeopleSoft Query Tips and Tricks"

Revision as of 20:53, 12 November 2008

PSV9 > Oracle Knowledge Base

Oracle Nuances

Oracle dates in the field list

The DB2 DATE() function corresponds to TRUNC() in Oracle, but TRUNC() will not work on a DateTm field once PeopleTools has (automatically) wrapped it in "TO_CHAR([datetime],'YYYY-MM-DD-HH24.MI.SS."000000"'). Instead, doing a SUBSTR([datetime], 1, 10) will return an actual date, which PeopleTools formats as 'MM/DD/YYYY', giving the same effective result as the DB2 DATE().

The DB2 functions YEAR(), HOUR(), etc. correspond to EXTRACT(YEAR FROM [date]) and EXTRACT(HOUR FROM [timestamp]) in Oracle, but PeopleTools does not allow these functions in an Expression because of the FROM keyword. Use SUBSTR() instead to get the desired portion of the field.

Using an expression involving date math, such as addition or subtraction of days, becomes difficult if the expression is used in the field list. This is because PeopleTools will wrap any fields used in the expression in a TO_CHAR function. For example, the expression "CURRENT_DATE - [datetime]" will normally work, but if it is used in the field list, PeopleTools changes it to be "CURRENT_DATE - TO_CHAR([datetime], 'YYYY-MM-DD')". This expression won't work. To get around this problem, wrap the field in a TO_DATE function when you create the expression. For example:

CURRENT_DATE - TO_DATE([datetime], 'YYYY-MM-DD') <-- This will turn the character representation back into a date.

IMPORTANT NOTE: if you need to use the expression in both criteria and display it in the field list, you need to create two separate expressions, one that wraps the date with TO_DATE() for display and one that does not for use in your criteria.

Oracle dates in the criteria

In v8, DateTm fields were wrapped in a DB2 DATE() function when used in criteria. In v9, TRUNC() is the equivalent function, but is not always necessary. Most comparisons (<, <=, etc) can be done on the field itself. If the criterion is = (equal to), you may not get any results unless you truncate the DateTm.

Oracle times in the criteria

To do time comparisons, use character representations of the 24-hour clock time. For example, to return all rows where a timestamp is after 5:00 PM, the criterion would be

TO_CHAR([DateTm], 'HH24:MI:SS') > '17:00:00'

Long text fields with DISTINCT or GROUP BY

If you have a long text field (like a comments field) in your query results, and you use the DISTINCT option on the query or you are grouping by the long text field, you'll receive the following Oracle error.

ORA-00932: inconsistent datatypes: expected - got CLOB 

To work around this - either remove the DISTINCT if applicable, or create an expression that converts the long character using TO_CHAR().

TO_CHAR(A.COMMENTS)

Make the Expression Type = Long Character

PSQuery Limitations

Maximum of 26 records

PSQuery can have a maximum of 26 records in a query. This limitation is a result of how aliases are assigned to the recrods, namely via the alphabet [A-Z], and there is no handling for what happens after the "Zth" table is added. It does not assign an alias and the query breaks.

Other PSQuery Tips

Adding Oracle Hints to PSQueries

I haven't tried it yet, but here is a step-by-step on adding an Oracle optimizer hint to a PSQuery