SQL Notes: INSERT INTO and DELETE Statements

Mini SQL Lesson #5

I am learning SQL through the W3Schools Tutorial. If you want to do exercises and follow along in-browser, please check out the link!

Finally time to learn how to add and delete records in a table!

INSERT INTO [table] (field_1, field_2, ...)
VALUES (value1, value2, ...),
(value3, value4, ...),
(value5, value6, ...);

• INSERT INTO inserts new records into a table.

• field names may be omitted if you are entering values into all fields of a table. If you enter values only into specific fields, other fields in the record will return null.

• Multiple new records can be added by comma-separating between records.

Example:

INSERT INTO Cars
VALUES ('13954', 'Toyota', 'AE86', '1983', 'White'),
('35000', 'Trans Am', '20000 WR', '2009', 'Yellow' );

Notice since I included a value for every field, I did not need to declare which fields to add new values into.

INSERT INTO Cars (Make, Model, Color)
VALUES ('Chevrolet', 'Camaro', 'Yellow');

Since I specified I only wanted to put values in Make, Model, and Color, the VIN and Year fields contain null values.

DELETE FROM [table] WHERE condition

• Deletes record(s) that meet the specified condition

• WARNING: Include the condition, otherwise you will delete ALL RECORDS on the table.

• If you use DELETE FROM on an entire table, you will delete all records but the table (it's structure, attributes, and indexes) will remain.

• To delete a table use DROP TABLE [table].

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