Cursor For Volatile Table in Teradata

Question

I have a volatile table (say, vtTempTableForPI) that I am creating inside a procedure. Once the volatile table gets created, I am inserting rows into it. Once I have records in the volatile table, I need to take MAX(ModifiedDatetime) from this volatile table (vtTempTableForPI) into a local variable. However, I am unable to find a way to do so.

Here is a piece of code from my procedure for some context:

SELECT MAX(ModifiedDatetime)
    FROM vtTempTableForPI
    INTO lvMaxUpdateDateTime
    WHERE Template = 'Schedule_Stream'
;

And then I want to use this local variable to insert into another volatile table, like below:

SET lvQuery = '
    INSERT INTO vtScheduleVersionUpdatedTime
    SELECT
          ''Schedule_Stream''
        , ''' || CAST(lvMaxUpdateDateTime AS VARCHAR(19)) || '''
';
EXECUTE IMMEDIATE lvQuery;

I can't use this cursor on volatile table since its definition will not be present in DBC when we compile the procedure, so it will give an error. If I try to use dynamic query in order to avoid this error, I run into another error like below:

            SET lvMaxModifiedDateQuery = '
                SELECT MAX(ModifiedDatetime)
                FROM vtTempTableForPI
                WHERE Template = ''Schedule_Tank''
            ';

            PREPARE stMaxModifiedDateQuery03 FROM lvMaxModifiedDateQuery;
            OPEN crGetMaxModifiedDate03;
            FETCH crGetMaxModifiedDate03 INTO lvMaxUpdateDateTime;
            --CLOSE crGetMaxModifiedDate;

            SET lvQuery = '
                INSERT INTO vtScheduleVersionUpdatedTime
                SELECT
                      ''Schedule_Tank''
                    , ''' || CASt(lvMaxUpdateDateTime AS VARCHAR(19)) || '''
            ';
            EXECUTE IMMEDIATE lvQuery;

Below is the error that I am getting:

Failure occured while Creating Dynamic Query
                    SQL State:T7688,
                    SQL Code:7688,
                    SQL SESSION:  252898254,
                    Execution Start Time:2019-01-13 21:44:44,
                    Execution End Time:2019-01-13 21:44:54,
                    ERROR Message: Error occurred generating Evl code for dynamic fetch.

Need help!

Answer 1

What's your Teradata release? This is working fine for me:

REPLACE PROCEDURE SP_test(
        IN v_CALC_BASIS  VARCHAR(100))

BEGIN   
   DECLARE lvMaxUpdateDateTime INT;
   DECLARE v_LogStmt VARCHAR(5000);

   SELECT Max(ModifiedDatetime)
       FROM vtTempTableForPI
       INTO lvMaxUpdateDateTime
       WHERE Template = 'Schedule_Stream'
   ;
END;

CALL SP_test ('bla');

CALL Failed.  [3807] SP_TEST:Object 'vtTempTableForPI' does not exist.

Either create the Volatile Table before you compile it or simply switch to a Global Temporary Table instead (recommended) .