SQL INSERT INTO

SQL > SQL Commands > Insert Into Statement

In the previous sections, we have seen how to query information from tables. But how do these rows of data get into these tables in the first place? This is what this and the next section, covering the INSERT INTO statement, as well as the following section, covering tbeUPDATE statement, are about.

In SQL, there are basically two ways to INSERT data into a table: One is to insert it one row at a time, the other is to insert multiple rows at a time. In this section, we'll take a look at the first case:

The syntax for inserting data into a table one row at a time is as follows:

INSERT INTO "table_name" ("column1", "column2", ...)
VALUES ("value1", "value2", ...);

Assuming that we have a table that has the following structure,

Table Store_Information

Column Name	Data Type
Store_Name	char(50)
Manager_ID	integer
Sales	float
Txn_Date	datetime

and now we wish to insert one additional row into the table representing the sales data for Los Angeles on January 10, 1999. On that day, this store had $900 in sales, and the Manager_ID for this store is 10. We will use the following SQL script:

INSERT INTO Store_Information (Store_Name, Manager_ID, Sales, Txn_Date)
VALUES ('Los Angeles', 10, 900, 'Jan-10-1999');

Now the table will hold the following data:

Table Store_Information

Store_Name	Manager_ID	Sales	Txn_Date
Los Angeles	10	900	Jan-10-1999

Please note that we can specify the column names in any order -- the order does not have to be the same as that of the table. For example, the SQL statement before is equivalent to the SQL statement above:

INSERT INTO Store_Information (Sales, Store_Name, Manager_ID, Txn_Date)
VALUES (900, 'Los Angeles', 10, 'Jan-10-1999');

Not Specifying Column Name In INSERT INTO Statement

If we leave off the column names in the INSERT INTO statement, we will need to make sure that the data is inserted in the same column order as that in the table. For example,

INSERT INTO Store_Information
VALUES ('Los Angeles', 10, 900, 'Jan-10-1999');

will give us the desired result, while

INSERT INTO Store_Information
VALUES (900, 'Los Angeles', 10, 'Jan-10-1999');

will result in Store_Name being set to 900, Manager_ID being set to 'Los Angeles', and Sales being set to 10. Clearly this is not what we intended to accomplish.

Inserting Into Some Columns

In the above examples, we insert a value for every column in the table. Sometimes, we may decide to insert value into some of the columns and leave the rest of the columns blank. For those cases, we simply specify the columns that we want to insert values into in our SQL statement, such as in the following example:

INSERT INTO Store_Information (Store_Name, Sales, Txn_Date)
VALUES ('New York', 500, 'Jan-10-1999');

Now the table becomes:

Table Store_Information

Store_Name	Manager_ID	Sales	Txn_Date
Los Angeles	10	900	Jan-10-1999
New York		500	Jan-10-1999

In this case, the value for the Manager_ID column in the second row is NULL. NULL means that data does not exist, and we discuss the concept of NULL later in this tutorial.