The abbreviation SQL stands for Structured Query Language. SQL commands tell a database how to perform operations, functions, and queries on data. SQL commands can be used to search the database as well as to create tables, add data to tables, change data, and drop tables. If you’re going to work with SQL, you should know how to use the following fundamental SQL commands.
SELECT and FROM: A query’s SELECT clause determines which data columns should be displayed in the results. Options can also be used to display data that isn’t contained in a table column.
CHECK: The CHECK constraint is used to limit the number of possible values for a column.
When a CHECK constraint is applied to a single column, only certain values are permitted. The CHECK constraint in a table can constrain the values in some columns based on the values in other columns in the row.
ALTER TABLE: ALTER TABLE changes the structure of a table.
CREATE TABLE: CREATE TABLE creates a database table precisely what it says on the tin. You can give the table a name and select the columns it should contain.
WHERE: Use the WHERE clause to limit the number of rows.
SELECT: SELECT command and the results without a WHERE statement. Then, in a WHERE statement, we’ll use all five qualifiers listed above.
UPDATE: To update a record in a table, use the UPDATE statement. Use the WHERE condition to specify the records you want to update. At the same time, one or more columns can be updated.
GROUP BY: GROUP BY allows you to merge rows and aggregate data.
HAVING: HAVING allows you to filter the data obtained by the GROUP BY clause so that just a subset of the entries is visible to the user.
AS: you can rename a column or table by using an alias.
ORDER BY: Sorting the result set by one or more of the SELECT section’s items is possible with ORDER BY. Here’s a SQL statement that sorts the students by FullName in descending order. Although ascending (ASC) is the usual sort order, you can use DESC to sort in the opposite direction (descending).
COUNT: COUNT counts the number of rows in the result set and displays it as a column.
DELETE: DELETE is a command that deletes a record from a database table.
INNER JOIN: Inner Join, selects records from two tables that have values that match.
LEFT JOIN: The matched rows from the right table, as well as all rows from the left table, are returned via a LEFT JOIN.
RIGHT JOIN:
A RIGHT JOIN returns all rows from both tables, as well as the matched rows from the left table.
FULL OUTER JOIN: The Full OUTER JOIN retrieves all rows from both tables that match.
Final Thoughts: These are the fundamental SQL commands. If you want to learn more about SQL, you can always learn for free on youtube. There are thousands of SQL tutorials on YouTube. Use Career Ninja‘s LearnTube for hand-holding training on YouTube. LearnTube organizes the results of your YouTube search into a course framework. If you want to learn “SQL tutorials”, search the term on LearnTube and it will show you a bunch of youtube videos like an online course. As a beginner, you’ll click through the videos from the first to the last, as if you were taking an online course tailored specifically for you.
