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In the last blog we have discussed about SQL operators ,wildcards and aggragate functions. In this blog we are going to see ALTER command and its use cases, Order By and NULL Values.

So let's get started 🔥



Now here we need to add one more column to table and i.e. Grade column. Here's how we can do it -:



So initially the column will contain NULL values as we have not specified any default value here.

Now the important thing is how can we add data into this as per our existing data?

So this is a tricky part here we can either introduce a formula and assign grades to each student as per that formula.







Here "ASC" refers ascending order.

NULL Values in SQL

An empty field in SQL which is not being explicitly initialized is set to NULL. As you have seen above when we added "Grade" column to our table, it was empty initially.

Is Null operator

The IS NULL operator is used to test for empty values (NULL values).

So these were Alter command, Order By and Null values in SQL.

In the next blog we will see keys and joins.

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