What Are Some Good MySQL Cheat Sheets

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All your interaction with the database is done by passing messages to the MySQL server. The MySQL server needs to be able to understand the instructions you are sending to it. You communicate with Structured Query Language (SQL), a standard computer language that most database management systems understand at least in some form.

To make a query that MySQL can understand, create a SQL statement and send it to the MySQL server.

Create SQL queries

SQL is almost English; It is mostly made up of English words put together into phrases that sound similar to English sentences. In general (luckily) you don't need to understand arcane technical language to write working SQL queries.

The first word of each statement is its name, an action word (verb) that tells MySQL what you want to do. The statements discussed here are CREATE, DROP, ALTER, SHOW, INSERT, LOAD, SELECT, UPDATE, and DELETE. This basic vocabulary is sufficient to create and interact with databases on websites.

The statement name is followed by words and phrases - some required and some optional - that tell MySQL how to perform the action. For example, you always need to tell MySQL what to create, and you always need to tell it which table to insert data into or to select data from.

The following is a typical SQL statement. As you can see, English words are used:

SELECT lastName FROM member

When a statement uses SELECT, it is called a query because you are querying the database for information. This query gets all of the last names that are stored in the table named Members. More complicated queries like the following are less English-language:

SELECT lastName, firstName FROM member WHERE state = "CA" AND city = "Fresno" ORDER BY lastName

This query retrieves all of the last and first names of members who live in Fresno. then sorts them alphabetically by last name. Although this query is less in English, it's still pretty clear.

Here are some general points to keep in mind when creating an SQL statement:

  • Capitalization: In this example, SQL language words are capitalized; Items of variable information (such as column names) are usually labeled, all or most of which are lowercase. This makes it easier for you to read -MySQL does not require this format. The case of the SQL words doesn't matter; For example, select is the same as SELECT and from is the same as FROM as far as MySQL is concerned.

    On the other hand, the case of the table names, column names, and other variable information is important if your operating system is Unix or Linux. If you are using Unix or Linux, MySQL must match the column names exactly, so the case for the column names must be correct - for example, last name is not the same as last name.

    Windows is not as picky as Unix and Linux, however; From his point of view, last name and surname are identical.

  • Distance: SQL words must be separated by one or more spaces. It doesn't matter how many spaces you use. You might as well use 20 slots or just 1 slot. SQL also doesn't pay attention to the end of the line. You can start a new line at any point in the SQL statement, or you can write the entire statement on one line.

  • Quotes: Note that CA and Fresno are enclosed in double quotation marks (") in the previous query. CA and Fresno are a series of characters that Text strings, or Strings are called. You are asking MySQL to compare the text strings in the SQL query with the text strings already stored in the database. When comparing numbers (such as integers) that are stored in numeric columns, do not enclose the numbers in quotation marks.

Send SQL queries

There are several ways to send an SQL query to MySQL. Here are two methods of sending queries:

  • The MySQL client: When you install MySQL, a text-based MySQL client is automatically installed. This simple client can be used to send queries.

  • Built-in PHP functions: You communicate with a MySQL database from PHP scripts using PHP functions specially designed for this purpose. The functions connect to the MySQL server and send the SQL query.