3-sql command

Source: Internet
Author: User
Tags create index numeric value

Some of the most important SQL commands
    • SELECT -Extract data from the database
    • Update-Updates the data in the database
    • Delete-deletes data from the database
    • INSERT INTO-inserts new data into the database
    • CREATE database-creating new databases
    • alter database-Modify Databases
    • CREATE TABLE-Creates a new table
    • ALTER TABLE -Change (change) database table
    • Drop Table-delete tables
    • CREATE index-Creating indexes (search key)
    • Drop Index-delete indexes

1 Select


2 where

The following operators can be used in the WHERE clause: SQL uses single quotation marks to wrap text values (most database systems also accept double quotes). If it is a numeric value, do not use quotation marks.

operator Description
= Equals
<> Not equal to
> Greater than
< Less than
>= Greater than or equal
<= Less than or equal
Between Within a range
Like Search for a pattern

The and and or operators are used to filter records based on more than one condition.


(ORFirstname= ' William ' ) AND lastname= ' Carter '


3-sql command

Contact Us

The content source of this page is from Internet, which doesn't represent Alibaba Cloud's opinion; products and services mentioned on that page don't have any relationship with Alibaba Cloud. If the content of the page makes you feel confusing, please write us an email, we will handle the problem within 5 days after receiving your email.

If you find any instances of plagiarism from the community, please send an email to: info-contact@alibabacloud.com and provide relevant evidence. A staff member will contact you within 5 working days.

A Free Trial That Lets You Build Big!

Start building with 50+ products and up to 12 months usage for Elastic Compute Service

  • Sales Support

    1 on 1 presale consultation

  • After-Sales Support

    24/7 Technical Support 6 Free Tickets per Quarter Faster Response

  • Alibaba Cloud offers highly flexible support services tailored to meet your exact needs.