Used in situations with SQL queries that do not allow the use of the WHERE keyword.Ĭopies data originating in a table into another table. Works with aggregate functions, grouping the result-set in at least one column. The default is ascending while the DESC keyword changes it to descending. Sorts your results in descending or ascending order. There is also a SELECT DISTINCT statement, which will only return values that are different. Selects the relevant data from your database and returns it in a result-set, which is the result table. ĭeletes the records currently existing in a table.
Lets you choose which database you will be performing operations on using your SQL queries. Data Manipulation Language Commandsĭata Manipulation Language (DML) SQL queries and commands manipulate data within the database.
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Makes a full backup of your specified database.Īdding WITH DIFFERENTIAL to the end of the code will back up only the elements that have changed since your last full backup. You can also use ALTER TABLE statements combined with ALTER/MODIFY COLUMN to change the column’s datatype. You can combine ALTER TABLE commands with DROP or ADD COLUMN commands, which will delete and add columns, respectively. Modifies, deletes or adds columns within your existing table. These types of SQL queries should also be performed with caution as information will be lost, leaving an empty table. Use these SQL commands with caution, as they result in the complete loss of the information within the database or table.ĭeletes information within a table without deleting the table itself. For example: CREATE DATABASE and CREATE TABLE create a database and a table, respectively while CREATE TABLE AS creates a table using an existing one.ĭrops a database or table that currently exists.Īs with CREATE, examples include DROP DATABASE and DROP TABLE, which drop the existing database and table, respectively. Data Definition Language Commandsĭata Definition Language (DDL) SQL queries and commands help define the database.Ĭreates a database or table. To make SQL queries and commands easier to understand, most coders divide them into several categories. However, once you get a firm grip on the basics, you can start exploring more advanced ones. Depending on your skill level and desired use, they can be relatively straightforward or complex. A web coding bootcamp will likely cover SQL queries and commands.
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