What is a use of SQLWARN3 in a SQLCA? Explain with the help of a practical example?

The SQLWARN3 field in SQLCA is used to detect the condition wherein the number of the resultant columns is greater than the number of host variables given in the query of a COBOL-DB2 program. The SQLWARN3 is a 1 byte field, which contains the value ‘W’when there is mismatch in number of columns returned by the query and number of host variables used.

We can enquire the status of SQLWARN3 using IF or EVALUATE statements as in the below example

A010-CHECK-ORDER.
EXEC SQL
   SELECT ORDER_DATE,
         ORDER_TOTAL
      INTO :ORDER-DATE,
      FROM ORDERS
      WHERE ORDER_ID = :ORDER-ID
END-EXEC
   EVALUATE SQLWARN3
      WHEN ‘W’
         DISPLAY ‘MISMATCH IN COLUMNS & HOST VARIABLES’
      WHEN OTHER
         DISPLAY ‘QUERY EXECUTED SUCCESSFULLY’