Syllabus Detail

  • SQL insert, update and select queries 12 ATAR


  • SQL stands for Structured Query Language
  • It's considered one of the most common languages used to communicate with databases
  • SQL is how we can input and retrieve information from a datbase, as well as update, edit and even remove
  • A general SQL query will follow the structure: SELECT [x] FROM [y] WHERE [z]
    • Where [x] is a database, [y] is a table and [z] is the condition
  • SQL is heavily English-based which makes it easy to understand and work with


SQL Queries and an Example

  • "SELECT" begins our SQL query
  • It tells the database what information we wish to view from the proceeding query
  • Examples of information to select are: "* (Wildcard; all"), "FirstName", "LastName", "Gender"

  • "FROM" tells the database where to look for this information
  • This is where we input the name of the table we want the query to search
  • For example, the "Students" table within our database

  • "WHERE" represents the conditions of the search results
  • This means that we can filter our results by providing a search term
  • For example, "WHERE `FirstName` = `Bobby`" will only show results that contain Bobby as the value for the FirstName field

  • "ORDER BY" is the only way to order data in SQL alone
  • It accepts options such as ASC (ascending) and DESC (descending)
  • To select all male students and order them by last name we'd do the following:
  • SELECT `FirstName`, `LastName` FROM `Students` WHERE `Gender` = `Male` ORDER BY `LastName` DESC

  • "UPDATE" allows us to update data that already exists within a field
  • For example, UPDATE `Students` SET `Gender` = `Male` WHERE `Gender` = `Female`
  • This would update our Students table and turn all students male

  • "DELETE" allows us to delete data from within our database
  • For example, DELETE * FROM Students
  • This would delete all records from the Students table

  • "INSERT INTO" allows us to insert new data in to our database
  • For example, INSERT INTO Students VALUES (FirstName, LastName, Gender)
  • This would allow us to insert a new student in to the Students table with appropriate values


Further Research

  • Read more about SQL and how it works at NTCHosting here
  • Read more about MySQL, databases and SQL from here


Worksheet and Practice (yet to be added)

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