Examine the structure and data of the CUST_TRANS table: 
Dates are stored in the default date format dd-mon-rr in the CUST_TRANS table. Which three
SQL statements would execute successfully?
A.
SELECT transdate + ’10’ FROM cust_trans;
B.
SELECT * FROM cust_trans WHERE transdate = ’01-01-07′;
C.
SELECT transamt FROM cust_trans WHERE custno > “11”;
D.
SELECT * FROM cust_trans WHERE transdate=’01-JANUARY-07′;
E.
SELECT custno + ‘A’ FROM cust_trans WHERE transamt > 2000;
Explanation:
In option C, it’s ’11’ instead of “11”, in that case, it is a valid SQL statement.
you got it.
?
Correct B,D,E
B is not correct, it throws an error: ORA-01843: not a valid month.
E isn’t correct also, error: ORA-01722: invalid number.
Correct answers are:
A,C,D.
Sorry, C is not correct – Sergio explain it.
I’m sorry why A is correct? What is the result of transdate + ’10’? Isn’t transdate a date type? If transdate + 10 it is correct but ’10’ it’s a character data type? Thanks in advance
Transdate in this example is the column name, see the describe table output.
That means that the ‘transdate’ will be replaced by a value stored in the table and added to 10.
A,C,D are correct.
I still can’t see how C can be correct. Using double quotes would raise an error.
If the statement was something else as Sergio suggests it would be correct, but then if any incorrect statement was something else, they could be correct.
Are these realy the questions that will be in the exam?
SQL> desc cust_trans;
Name Null? Type
—————————————– ——– —————————-
CUSTNO NOT NULL CHAR(2)
TRANSDATE DATE
TRANSAMT NUMBER(6,2)
SQL>
SQL> select TRANSAMT from cust_trans where CUSTNO > “11” ;
select TRANSAMT from cust_trans where CUSTNO > “11”
*
ERROR at line 1:
ORA-00904: “11”: invalid identifier
SQL>
SQL> select TRANSAMT from cust_trans where CUSTNO > 11;
TRANSAMT
———-
2000
3000
SQL>