In the event that you've made a vacant table in your data set you'll have to add records to it. In this article you will figure out how you can add records to your tables utilizing the INSERT articulation in SQL.
Remember that if the grammar introduced here doesn't work, you can check in the documentation for the execution of SQL you are utilizing. Most stuff works something very similar in all cases, yet there are a few contrasts.
SQL INSERT Statement Syntax
An INSERT statement specifies into which table you want to add a record. You write the command INSERT INTO table_name, then the keyword VALUES followed by the values you want to add in each column inside parenthesis and separated by commas, as below:
INSERT INTO table_name
VALUES (value1, value2, value3...);
The values will be added to the columns in the order in which the columns have been defined in the table.
How to Give a Value to the Selected Columns
Let's say that you instead want to give a value to only a few columns – for example if you want to avoid manually setting the id so it's done automatically. You would use the syntax below:
INSERT INTO table_name(column1, column2...)
VALUES (value1, value2...);
The values will be assigned to the columns in the order in which they are written in the parenthesis.
SQL INSERT Statement Examples
Let's create a table, and then we will use INSERT to add the first few records to it.
The code below will create a table named users that has 5 columns. We'll have an id column that will be the PRIMARY KEY (the column that will always have unique values and allow us to uniquely identify a row), and then the name, age, state, and email columns.
CREATE TABLE users (id INTEGER PRIMARY KEY AUTOINCREMENT, name TEXT, age INTEGER, state TEXT, email TEXT);
Let's add the first record to this table using the first syntax we looked at.
We will add the user Paul with an id of 1 , an age of 24, from the state of Michigan, and with an email address of paul@example.com using the query below:
INSERT INTO users
VALUES (1, "Paul", 24, "Michigan", "paul@example.com");
This will make the table look like this:
With this syntax you must have a value for each column or it will throw an error and not work.
Now let's add a couple other records, using the second kind of syntax seen above.
INSERT INTO users (name, state)
VALUES ("Molly", "New Jersey");
INSERT INTO users (name, state, age)
VALUES ("Robert", "New York", 19);
In this case the first value is assigned to the first mentioned column, so "Molly" is assigned to the name column, and "New Jersey" to the state column. Then for the other record, the column name is given the value of "Robert", the column state gets "New York", the column age is assigned 19.
What happens to the columns that have not been assigned a value? The column with a type of INTEGER PRIMARY KEY AUTOINCREMENT is updated automatically, making sure that each row has a unique value. When a value is not specified for other columns, they are assigned a value of NULL.
Now the table looks like the below. Note that the id column has been updated to have unique values in each row, even if we have not explicitly assigned a value to it. The other columns that have not been assigned a value have a value of NULL.
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