SQL GROUP BY Clause The GROUP BY clause is used to summarize data based on grouping criteria. For each group one column is returned in result set. Syntax SELECT expression1, expression2, … expressionN, aggregate function (aggregate expression) FROM Table...
SQL IN Operator You can specify multiple values with IN operator and it will return matching values from WHERE clause of a table. IN operator matches values in a list or subquery and returns the output. Syntax SELECT column1, column2,… columnN FROM TableName...
SQL AND & OR Operators SQL AND operator is used to filter the records by combining two boolean expressions and returns true when both boolean expressions are true whereas SQL OR operator returns true value when either the first condition or the second...
What are records? Records are another type of datatypes which oracle allows to be defined as a placeholder. Records are composite datatypes, which means it is a combination of different scalar datatypes like char, varchar, number etc. Each scalar data...
Variables In PLSQL Variables must be declared first before the usage. The PL/SQL variables can be a scalar type such as DATE, NUMBER, VARCHAR(2), DATE, BOOLEAN, LONG and CHAR, or a composite type, such array type VARRAY. Only TRUE and FALSE can be assigned...
CREATE OR REPLACE PACKAGE test AS -- package spec TYPE list IS VARRAY(25) of NUMBER(3); PROCEDURE hire_employee (emp_id INTEGER, name VARCHAR2); PROCEDURE fire_employee (emp_id INTEGER); PROCEDURE raise_salary (emp_id INTEGER, amount REAL); END test;...
Writing PL/SQL Procedures/Functions PL/SQL functions returns a scalar value and PL/SQL procedures return nothing. Both can take zero or more number of parameters as input or output. The special feature about PL/SQL is that a procedure/function argument...
Write a Query To Delete The Repeated Rows from emp table; SQL>Delete from emp where rowid not in(select min(rowid)from emp group by ename) TO DISPLAY 5 TO 7 ROWS FROM A TABLE SQL>select ename from emp where rowid in(select rowid from emp where rownum<=7...
Partitions Partition is a data base object, it allows VLDB objects (Very Large Databases such as tables, indexes etc). By splitting large database objects into smaller, more manageable units. You can divide the rows of a single table into different parts...
Explain Plan Explain Plan : It is a statement that allows you to have oracle generate execution plan for any sql statement with out actually executing it.You will be able to examine the execution plan by querying the plan table. Plan Table : A Plan table...
