UPDATE and DELETE
It's time to get back to writing queries and consider two more statements.
You already know how to clear a table, add a column, insert data, etc. But for proper interaction with the database, we need to understand how to update and delete individual rows.
For this, there are two statements and types of queries: the UPDATE and the DELETE queries.
Let's look at an example with the medications table:
Let's imagine we need to update the price for a specific type of medication. For example, currently, there's a 50% discount on ibuprofen, and we need to change the price for this product.
Our UPDATE query will look like this:
1234567UPDATE medications SET price = 4 WHERE id = 2; SELECT * FROM medications ORDER BY id;
Here, we updated the medications table so that the price for the product with id 2 (ibuprofen) will be set to 4. After that, we selected all the columns from the table to ensure the price column was successfully updated. You can substitute any value and see how the update operation works in SQL:
UPDATE table_name
SET column_name = value
WHERE some_condition;
The syntax for deletion will look like this:
DELETE FROM table_name
WHERE some_condition;
But I'll remind you that deleting rows should be done with caution, as you won't be able to simply recover them.
Note
If you don't include a
WHEREcondition, the data will be updated or deleted for all rows.
Swipe to start coding
In the pharmaceutical market, there's inflation!
The supplier company informed us that we must urgently establish a minimum price of 10 units for the product. So your task will be to update the table so that the price, which was previously less than 10, becomes 10. You can do this using the UPDATE statement.
Brief Instructions
- Use the UPDATE statement to modify the
medicationstable. - Use SET to assign a new value of 10 to the
pricecolumn. - Use the WHERE clause with the condition
price < 10so that the update only applies to rows meeting this requirement.
Solution
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It's time to get back to writing queries and consider two more statements.
You already know how to clear a table, add a column, insert data, etc. But for proper interaction with the database, we need to understand how to update and delete individual rows.
For this, there are two statements and types of queries: the UPDATE and the DELETE queries.
Let's look at an example with the medications table:
Let's imagine we need to update the price for a specific type of medication. For example, currently, there's a 50% discount on ibuprofen, and we need to change the price for this product.
Our UPDATE query will look like this:
1234567UPDATE medications SET price = 4 WHERE id = 2; SELECT * FROM medications ORDER BY id;
Here, we updated the medications table so that the price for the product with id 2 (ibuprofen) will be set to 4. After that, we selected all the columns from the table to ensure the price column was successfully updated. You can substitute any value and see how the update operation works in SQL:
UPDATE table_name
SET column_name = value
WHERE some_condition;
The syntax for deletion will look like this:
DELETE FROM table_name
WHERE some_condition;
But I'll remind you that deleting rows should be done with caution, as you won't be able to simply recover them.
Note
If you don't include a
WHEREcondition, the data will be updated or deleted for all rows.
Swipe to start coding
In the pharmaceutical market, there's inflation!
The supplier company informed us that we must urgently establish a minimum price of 10 units for the product. So your task will be to update the table so that the price, which was previously less than 10, becomes 10. You can do this using the UPDATE statement.
Brief Instructions
- Use the UPDATE statement to modify the
medicationstable. - Use SET to assign a new value of 10 to the
pricecolumn. - Use the WHERE clause with the condition
price < 10so that the update only applies to rows meeting this requirement.
Solution
Switch to desktop for real-world practiceContinue from where you are using one of the options belowThanks for your feedback!
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