SQL - Creating Tables

create table employee

(first varchar(15),

last varchar(20),

age number(3),

address varchar(30),

city varchar(20),

state varchar(20));

Common Data types --

char(size) -- fixed lenght character string

varchar(size) -- variable lenght character string

number(size) -- number value with max number of column digits

date -- date value

number(side, d) -- number value with max digits to right of decimal

create table myemployees_RDP0680                  

(firstname varchar(15),

 lastname varchar(20),

title varchar(30),

age number(3),

salary number(7));

SQL -- conditional selections

In the last example the condition was first should equal 'Eric'. Besides equal here are other conditional clauses used in SQL:

= Equal

> Greater than

< Less than

>= Greater than or equal

<= Less than or equal

<> Not equal to

LIKE pattern matching operator, use "%" as character wild card

Here is an example:

select first,

       last,

       city

  from empinfo

where city <>

  'Payson';

SQL -- Selecting Data

select *

                from empinfo

                where first = 'Eric'

The above examples SQL query selects all (*) columns from the empinfo table where the first name is Eric. See result of the query below.

 

SQL -- Table Basics

Table Basics

Database system contains one of more objects called tables. Tables are uniquely identified by name and comprised of columns and rows. Columns contain column name and data type. Rows contain the records or data for the column (see example weather data table).