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UNDEFINE employee_num Use the double ampersand(&&) if you wantto reuse the ariable value without prompting the user each time: SELECT employee_id, last_name, job_id, &&column_name FROM employees ORDER BY &column_name Use DEFINE command to create and assign a value to a variable Use UNDEFINE command to remove a variable DEFINE employee_num = 200 SELECT employee_id,last_name, salary, department_id..

UNDEFINE employee_num Use the double ampersand(&&) if you wantto reuse the ariable value without prompting the user each time: SELECT employee_id, last_name, job_id, &&column_name FROM employees ORDER BY &column_name Use DEFINE command to create and assign a value to a variable Use UNDEFINE command to remove a variable DEFINE employee_num = 200 SELECT employee_id,last_name, salary, department_id..

single-ampersand(&) or double-ampersand(&&) & : temporary && : Use subtitution variables to supplement the following - WHERE condition - ORDER BY clause - Column expressions - Table names - Entire SELECT statements Predefine variables by using DEFINE

single-ampersand(&) or double-ampersand(&&) & : temporary && : Use subtitution variables to supplement the following - WHERE condition - ORDER BY clause - Column expressions - Table names - Entire SELECT statements Predefine variables by using DEFINE

Sorting in descending order SELECT last_name,job_id,department_id, hire_date FROM employees ORDER BY hire_date DESC;Sorting by column alias SELECT employee_id,last_name,salary*12 annsal FROM employees ORDER BY annsal;Sorting by multiple columns SELECT last_name,department_id,salary FROM employees ORDER BY department_id,salary DESC; - NULL values are displayed last for ascending sequences and fir..

Sorting in descending order SELECT last_name,job_id,department_id, hire_date FROM employees ORDER BY hire_date DESC;Sorting by column alias SELECT employee_id,last_name,salary*12 annsal FROM employees ORDER BY annsal;Sorting by multiple columns SELECT last_name,department_id,salary FROM employees ORDER BY department_id,salary DESC; - NULL values are displayed last for ascending sequences and fir..

Sort retrieved rows with the ORDER BY clause ASC : ascending order, default DESC : descending order The ORDER BY clause comes last in the SELECT statement SELECT last_name,job_id,department_id,hire_date FROM employees ORDER BY hire_date; Syntax SELECT expr FROMtable [WHEREcondition(s)] [ORDER BY{column, expr, numeric_position} [ASC|DESC]};

Sort retrieved rows with the ORDER BY clause ASC : ascending order, default DESC : descending order The ORDER BY clause comes last in the SELECT statement SELECT last_name,job_id,department_id,hire_date FROM employees ORDER BY hire_date; Syntax SELECT expr FROMtable [WHEREcondition(s)] [ORDER BY{column, expr, numeric_position} [ASC|DESC]};

AND : Returns TRUE if both component conditions are true False > Null > TrueSELECT employee_id, last_name,job_id,salary FROM employees WHERE salary >= 10000 and job_id LIKE '%MAN%'OR : Returns TRUE if either component conditions are true True > Null > FalseSELECT employee_id, last_name,job_id,salary FROM employees WHERE salary >= 10000 or job_id LIKE '%MAN%'NOT : Returns TRUE if the following co..

AND : Returns TRUE if both component conditions are true False > Null > TrueSELECT employee_id, last_name,job_id,salary FROM employees WHERE salary >= 10000 and job_id LIKE '%MAN%'OR : Returns TRUE if either component conditions are true True > Null > FalseSELECT employee_id, last_name,job_id,salary FROM employees WHERE salary >= 10000 or job_id LIKE '%MAN%'NOT : Returns TRUE if the following co..