Oracle SQL & PL/SQL

  Filtering & Sorting Data using SQL     Once you know the basics ( SELECT , FROM , WHERE ), filtering and sorting helps you get the exact rows from tables .   1. Filtering with Conditions ( AND , OR , NOT )  - Use WHERE to filter rows. - Combine with logical operators :     • AND: all conditions true      • OR: any condition true      • NOT: negate condition   - - All conditions true (AND) SELECT *  FROM employees WHERE department = 'Sales'    AND salary > 50000; -- Any condition true (OR) SELECT *  FROM employees WHERE department = 'Sales'     OR department = 'Marketing'; -- Negate condition (NOT) SELECT *  FROM employees WHERE NOT department = 'HR';   2. Pattern Matching with LIKE   - % = any sequence, _ = single char     • Names starting with 'J'      • Names with 4 letters starting with 'J'   - - N...

  List of Table Operations in SQL [ 1. CREATE , 2. INSERT , 3. UPDATE , 4. ALTER , 5. DELETE , 6. DROP , 7. TRUNCATE ] 1.      CREATE : To define a new Table. 2.     INSERT : Add rows to the table. 3.     UPDATE : Modify existing rows in the table. 4.     ALTER : Modify the structure of the table. 5.     DELETE : Remove Rows from the table. 6.     DROP : Removes the entire table. 7.     TRUNCATE : Removes the all rows of the table but it keeps the table structure. 1>       CREATE : To define a new Table.   CREATE TABLE jobs (     job_id INT PRIMARY KEY ,     job_title VARCHAR (100),     job_description TEXT ,     min_salary DECIMAL (10, 2),     max_salary DECIMAL(10, 2) ...

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> The " DUAL " table is a one row and one column table. The owner of this table is "SYS" but it's accessible to all the db users.  > It is having single column called as " DUMMY " > It is used to test SQL expression with out querying to the main/real tables.  Eg : 1> SELECT SYSDATE FROM DUAL; O.P : It will print current date and time.       2> SELECT 'Hello, Welcome to SQL' from DUAL; O.P :  3> SELECT 5*9 AS RESULT FROM DUAL; O.P:  #SQL #LEARNSQL #DUALTABLE

About Oracle Buffer :- All Commands of SQL are typed at the SQL prompt. Only one SQL statement is managed in the SQL buffer. The current SQL statement replaces the previous SQL statement in the buffer. The SQL statements can be divided into different lines within the SQL buffer. Only one line i.e, the current line can be active at a time in the SQL buffer. At SQL prompt, editing is possible only in the current SQL buffer line. Every statement of SQL should be terminated using semi colon " ; ". One sql statement can contain only one semi colon. To run the previous or current SQL statement in the bufer type " / " at SQL prompt. To open the SQL editor type " ED " at SQL prompt.