Oracle SQL

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DATABASE TRANSACTIONS DB transaction is start with any of them; When DML command is running. When DDL command is running. When DCL command is running. Transaction is started when a …

Chapter 6 – DML (Data Manipulation Language) You can add, delete or update data, using the Data Manipulation Language. INSERT : Adding data to a table. UPDATE : Changing data …

Chapter 5 – Selecting Data From Multiple Tables Usage of multiple tables in one query Combining tables – JOIN Different Types of SQL Join Left Outer Join Right Outer Join …

Chapter 4 – Group Functions AVG Function SUM Function MIN Function MAX Function COUNT Function DISTINCT Function GROUP BY Statement HAVING Statement   One row functions can be applied to …

OPERATOR PRECEDENCE   Let’s list the employees which JOB_ID is SA_REP or AD_PRES , and have salary more than 15000. SELECT first_name,last_name, job_id, salary FROM hr.employees WHERE job_id = 'SA_REP‘ …

IS NULL OPERATOR Let’s list the employees that have manager. SELECT first_name,last_name, manager_id FROM hr.employees WHERE manager_id IS not NULL;   LOGICAL OPERATORS AND : It returns TRUE if all …

CHAPTER 2 WHERE Conditions Comparison operators BETWEEN operator IN operator LIKE operator IS NULL operator Logical operators AND operator OR operator NOT operator ORDER BY operator   RESTRICTING ROWS WITH …

ARITHMETIC OPERATORS Arithmetic operations can be used on the data which type is ‘date’ or ‘number’. The priority of the operators is like below ;   USAGE OF THE ARITMETHIC …

SELECT Statement Selection : SQL statements are being used to returning the selected lines from related tables. Projection : SQL’s projection ability is being used to returning the selected columns …