EVALUATE behavior

If you had problems using EVALUATE function –  please look at the following SR that I just found. Apparently, the work-around is to use CAST function.

QL Request: SET VARIABLE QUERY_SRC_CD=’Report’,SAW_SRC_PATH=’/users/administrator/last_working_day test 1′;SELECT “Task Type”.Type saw_0, “Task – Creation Date”.Date saw_1, EVALUATE(‘num_of_working_days(%1,%2)’,”Task – Creation Date”.Date,”Task – Last Updated Date”.Date) saw_2, “Task – Last Updated Date”.Date saw_3 FROM “SPS – Operation” ORDER BY saw_0, saw_1, saw_2, saw_3

The query fails and the following error occurs.

ERROR
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Query Status: Query Failed: [nQSError: 46035] Datatype(DOUBLE PRECISION) nullable(1) unicode(1) external char(0) conversion to datatype(TIMESTAMP) nullable(1) unicode(0) external char(0) is not supported.

These columns are from W_DAY_D. These are type date which the function is expecting. The function returns a number.

BUSINESS IMPACT
———————–
The issue has the following business impact:
Due to this issue, this is holding up resolution of a critical issue on the delivery of the project – which plans to go live next Friday (30th October).

Cause

Comments
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The cause of this issue is that EVALUATE expects to return data with a data type that is the same as the data
type of the parameter.
This has been raised in : EVALUATE FUNCTION SHOULD RETURN DATA TYPE OF FUNCTION

The Bug explains that when you use this function:

EVALUATE(‘my_function(%1)’, logical_table.ROWID)

It will set the data type of the column to INT because ROWID is also INT. However my_function does not return an INT but a REAL.

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The above is what you are experiencing and why you get the error suggesting converting double precision to timestamp is not supported

[nQSError: 46035] Datatype(DOUBLE PRECISION) nullable(1) unicode(1) external char(0) conversion to datatype(TIMESTAMP) nullable(1) unicode(0) external char(0) is not supported.

Proposed Solution

Customer was asked to do an explicit CAST to set the datatype to the datatype of the value that will be returned by my_function.

So something like

CAST(EVALUATE(‘my_function(%1)’, logical_table.ROWID) AS FLOAT)

The above resolved the issue.