Using variables in PLSQL SELECT statement - sql

Question

I have a query that queries on ReportStartDate and ReportEndDate so I thought I would use variables in PLSQL. Not sure what I am missing here, but I get an error:
CLEAR;
DECLARE
varReportStartDate Date := to_date('05/01/2010', 'mm/dd/yyyy');
varReportEndDate Date := to_date('05/31/2010', 'mm/dd/yyyy');
BEGIN
SELECT
'Value TYPE',
1 AS CountType1,
2 AS CountType2,
3 AS CountType3
FROM DUAL;
SELECT COUNT (*)
FROM CDR.MSRS_E_INADVCH
WHERE 1=1
AND ReportStartDate = varReportStartDate
AND ReportEndDate = varReportEndDate
;
END;
/
The Error is:
Error starting at line 2 in command:
Error report:
ORA-06550: line 6, column 5:
PLS-00428: an INTO clause is expected in this SELECT statement
ORA-06550: line 8, column 5:
PLS-00428: an INTO clause is expected in this SELECT statement
06550. 00000 - "line %s, column %s:\n%s"
*Cause: Usually a PL/SQL compilation error.
*Action:
This happens in Toad as well as in SQL Developer.
What is the proper way of using the variables in my WHERE clause?

Answer 1

You cannot use SQL statements directly in a PL/SQL block ( unless you use EXECUTE IMMEDIATE). The columns will need to be fetched into variables ( which is what PL/SQL is telling you with PLS-00428: an INTO clause is expected in this SELECT statement error). So you'll have to rewrite your statements as below.
SELECT
'Value TYPE',
1 AS CountType1,
2 AS CountType2,
3 AS CountType3
INTO
V_VALUE_TYPE,
V_CountType1,
V_CountType2,
V_CountType3
FROM DUAL;
SELECT COUNT(*)
INTO V_COUNT
FROM CDR.MSRS_E_INADVCH
WHERE 1=1
AND ReportStartDate = varReportStartDate
AND ReportEndDate = varReportEndDate
Be sure to add Exception Handlers, since PL/SQL expects only 1 row to be returned. If the statement returns no rows, you'll hit a NO_DATA_FOUND exception - and if the statement fetches too many rows, you'll hit a TOO_MANY_ROWS exception.

Answer 2

The question you have to answer is what do you want to do with the data that has been selected?
Sathya gave you one approach - declare variables in your PL/SQL block and select the columns INTO those variables. Note that this requires that the SELECT statement returns exactly one row - any more or less rows will throw an error. Another way is to declare collection types using the BULK COLLECT option: http://oracletoday.blogspot.com/2005/11/bulk-collect_15.html
Yet another option is to have the procedure return a cursor. This is useful in the case where the calling code expects to be able to fetch the data that the procedure has selected:
PROCEDURE GET_MY_REPORT( varReportStartDate in date, varReportEndDate in date, cur out sys_refcursor) is
begin
OPEN cur FOR SELECT *
FROM CDR.MSRS_E_INADVCH
WHERE 1=1
AND ReportStartDate = varReportStartDate
AND ReportEndDate = varReportEndDate;
END GET_MY_REPORT;