Basics of SELECT statement (1) - SQL Strategy - A site to master SQL while executing it on the Web

Learn the basic syntax of the SELECT statement.

1. basic SELECT minute syntax

--Show all data

SELECT	Column name,Column name...
FROM	Table name

■How to write a SELECT statement

When using a SELECT statement, after the SELECT statement, enter a comma-separated list of column names; you can also use SELECT * (asterisk) to display all columns. Then, after the FROM statement, enter the Table name.

■practice

Now for the exercise, I will give you two questions.

Practice (1/2) Questions

From the EMP table, display ENAME (employee name), JOB (job), and SAL (salary).

Practice (1/2) Answers

SELECT ENAME,JOB,SAL FROM EMP

Describe the items to be displayed after SELECT, separated by commas, and the table after FROM.

Practice (2/2) Questions

Use * (asterisk) to display all records in the EMP table.

Practice (2/2) Answers

SELECT * FROM EMP

If you use "*", it means the same as if you had selected all columns.

2. use of operators

--Show SAL (salary) times 10

SELECT	EMPNO,SAL * 10
FROM	EMP

The SELECT statement can contain arithmetic expressions to display the results of calculations. The following operators can be used. Parentheses can also be used to specify the precedence of calculations.

operator	meaning
+	addition
-	subtraction
*	multiplication
/	division (arith)

Now for the exercise, I will give you one Question.

Exercise Question

You have decided to increase an employee's salary by 2%; from the EMP table, show the employee's name (ENAME) and the salary multiplied by 1.02 (SAL).

Exercise answer

SELECT NAME,SAL * 1.02 FROM EMP

Arithmetic expressions can be used with the column operator number.

This concludes [Basics of SELECT statement (1)].