The document provides an overview of the SELECT statement in SQL and its usage for selecting data from database tables. It describes how to select single columns, multiple columns, columns from multiple tables, and all columns. It also covers the WHERE clause, DISTINCT, AND/OR operators, NULL values, arithmetic operators, aggregate functions, GROUP BY, HAVING, and ORDER BY clauses. Examples are given for each concept.
4. Select Multiple Columns
SELECT COLUMN_NAME, COLUMN_NAME
FROM TABLE_NAME;
Example:
SELECT D.DEPTNO , D.DEPT_NAME
FROM DEPT D;
5. Select Columns From Multiple Tables
SELECT *
FROM TABLE_NAME TABLE_1, TABLE_NAME TABLE_2
WHERE TABLE_1.COLUMN_NAME = TABLE_2.COLUMN_NAME;
Example:
SELECT *
FROM DEPT D, EMP E
WHERE D.DEPTNO = E.DEPTNO
9. AND Operator
SELECT COLUMN_NAME
FROM TABLE_NAME
WHERE CONDITION_1 AND CONDITION_2;
Example:
SELECT D.DEPTNO
FROM DEPT D
WHERE D.DEPTNO = 10 AND D.LOCATION = ‘CHENNAI’;
10. OR Operator
SELECT COLUMN_NAME
FROM TABLE_NAME
WHERE CONDITION_1 OR CONDITION_2;
Example:
SELECT D.DEPTNO
FROM DEPT D
WHERE D.DEPTNO = 10 OR D.DEPTNO = 20;
11. Select Rows With NULL values
SELECT *
FROM TABLE_NAME
WHERE COLUMN_NAME IS NULL;
Example:
SELECT D.DEPTNO
FROM DEPT D
WHERE D.LOCATION IS NULL;
12. Select Rows Without NULL values
SELECT *
FROM TABLE_NAME
WHERE COLUMN_NAME IS NOT NULL;
Example:
SELECT D.DEPTNO
FROM DEPT D
WHERE D.LOCATION IS NOT NULL;
26. ORDER BY ASCENDING ORDER
SELECT *
FROM TABLE_NAME
ORDER BY COLUMN_NAME, COLUMN_NAME ASC;
Example:
SELECT *
FROM EMP E
ORDER BY E.EMPTNO ASC;
27. ORDER BY DESCENDING ORDER
SELECT *
FROM TABLE_NAME
ORDER BY COLUMN_NAME, COLUMN_NAME DESC;
Example:
SELECT *
FROM EMP E
ORDER BY E.EMPTNO DESC;
28. ORDER BY COLUMN POSITION
SELECT *
FROM TABLE_NAME
ORDER BY COLUMN_ORDER, COLUMN_ORDER;
Example:
SELECT *
FROM EMP E
ORDER BY 1,2 ;
29. IN Operator
SELECT *
FROM TABLE_NAME
COLUMN_NAME IN (VALUE,VALUE);
Example:
SELECT *
FROM EMP E
WHERE E.DEPTNO IN (10,20);
30. BETWEEN Operator
SELECT *
FROM TABLE_NAME
COLUMN_NAME BETWEEN START_RANGE AND END_RANGE;
Example:
SELECT *
FROM EMP E
WHERE E.DEPTNO BETWEEN 10 AND 30;