SELECT INTO v12

The SELECT INTO statement is an SPL variation of the SQL SELECT command, the differences being:

• That SELECT INTO is designed to assign the results to variables or records where they can then be used in SPL program statements.
• The accessible result set of SELECT INTO is at most one row.

Other than the above, all of the clauses of the SELECT command such as WHERE, ORDER BY, GROUP BY, HAVING, etc. are valid for SELECT INTO. The following are the two variations of SELECT INTO.

SELECT <select_expressions> INTO <target> FROM ...;

target is a comma-separated list of simple variables. select_expressions and the remainder of the statement are the same as for the SELECT command. The selected values must exactly match in data type, number, and order the structure of the target or a runtime error occurs.

SELECT * INTO <record> FROM <table> ...;

record is a record variable that has previously been declared.

If the query returns zero rows, null values are assigned to the target(s). If the query returns multiple rows, the first row is assigned to the target(s) and the rest are discarded. (Note that "the first row" is not well-defined unless you’ve used ORDER BY.)

You can use the WHEN NO_DATA_FOUND clause in an EXCEPTION block to determine whether the assignment was successful (that is, at least one row was returned by the query).

This version of the emp_sal_query procedure uses the variation of SELECT INTO that returns the result set into a record. Also note the addition of the EXCEPTION block containing the WHEN NO_DATA_FOUND conditional expression.

CREATE OR REPLACE PROCEDURE emp_sal_query (
    p_empno         IN emp.empno%TYPE
)
IS
    r_emp           emp%ROWTYPE;
    v_avgsal        emp.sal%TYPE;
BEGIN
    SELECT * INTO r_emp
        FROM emp WHERE empno = p_empno;
    DBMS_OUTPUT.PUT_LINE('Employee # : ' || p_empno);
    DBMS_OUTPUT.PUT_LINE('Name       : ' || r_emp.ename);
    DBMS_OUTPUT.PUT_LINE('Job        : ' || r_emp.job);
    DBMS_OUTPUT.PUT_LINE('Hire Date  : ' || r_emp.hiredate);
    DBMS_OUTPUT.PUT_LINE('Salary     : ' || r_emp.sal);
    DBMS_OUTPUT.PUT_LINE('Dept #     : ' || r_emp.deptno);

    SELECT AVG(sal) INTO v_avgsal
        FROM emp WHERE deptno = r_emp.deptno;
    IF r_emp.sal > v_avgsal THEN
        DBMS_OUTPUT.PUT_LINE('Employee''s salary is more than the '
            || 'department average of ' || v_avgsal);
    ELSE
        DBMS_OUTPUT.PUT_LINE('Employee''s salary does not exceed the '
            || 'department average of ' || v_avgsal);
    END IF;
EXCEPTION
    WHEN NO_DATA_FOUND THEN
        DBMS_OUTPUT.PUT_LINE('Employee # ' || p_empno || ' not found');
END;

If the query is executed with a non-existent employee number the results appear as follows.

EXEC emp_sal_query(0);

Employee # 0 not found

Another conditional clause of use in the EXCEPTION section with SELECT INTO is the TOO_MANY_ROWS exception. If more than one row is selected by the SELECT INTO statement an exception is thrown by SPL.

When the following block is executed, the TOO_MANY_ROWS exception is thrown since there are many employees in the specified department.

DECLARE
    v_ename         emp.ename%TYPE;
BEGIN
    SELECT ename INTO v_ename FROM emp WHERE deptno = 20 ORDER BY ename;
EXCEPTION
    WHEN TOO_MANY_ROWS THEN
        DBMS_OUTPUT.PUT_LINE('More than one employee found');
        DBMS_OUTPUT.PUT_LINE('First employee returned is ' || v_ename);
END;

More than one employee found
First employee returned is ADAMS