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SQL Query List the EMPS Who Joined Before a Date

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August 15, 2015

SQL query to list the employees who joined before 1981

SELECT *
FROM EMP
WHERE HIREDATE < (’01-JAN-81’);

SQL SQL for Advanced Programmers

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SQL Query to display the EMPNO, ENAME, JOB, HIREDATE, EXP of all Managers

August 15, 2015

SELECT EMPNO , ENAME , JOB , HIREDATE , MONTHS_BETWEEN ( SYSDATE , HIREDATE ) EXP FROM EMP WHERE EMPNO IN ( SELECT MGR FROM EMP );

SQL Query to List the EMPS in ASC Order of Designations of those JOINED after the second half of a year

August 16, 2015

LIST THE EMPS IN THE ASC ORDER OF DESIGNATIONS OF THOSE JOINED AFTER THE SECOND HALF OF 1981. SELECT * FROM EMP WHERE HIREDATE > ( ’ 30 - JUN - 81 ’ ) AND TO_CHAR ( HIREDATE , ’ YYYY ’ ) = 1981 ORDER BY JOB ASC ;

Top myths for NULL value in SQL Queries

November 20, 2015

The below are some of the key points about nulls, and how to compare them. Just to make sure that you should know about what is NULL value. Interpretation is not exactly missing value. There could be many reasons why no value is present, e.g., value inappropriate. How to compare NULL to values In the below example the where condition just checks for TRUE condition. If not matches you will get UNKNOWN. Example: Table Name is: Sells bar beer price ======================= Joe's bar Bud NULL SELECT bar FROM Sells WHERE price < 2.00 OR price >= 2.00; ------------ ------------- UNKNOWN Conclusion Joe's Bar is not produced, even though the WHERE condition is correctly given. The reason is the price value is NULL. So, we should not compare NULL to values.