Database

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

There are essentially basically two ways to INSERT data into a table. One is to insert it one row at a time, and the other is to insert multiple rows at a time. Let’s first look at how we may INSERT data one row at a time:

Once we have the information in the table, we might find that there is a need to modify the data. To do so, we can use the UPDATE command. The syntax for this is

UPDATE “table_name”
SET “column_1” = [new value]
WHERE {condition}

It is easiest to use an example. Say we currently have a table as below:

Table Store_Information

We find that the sales for Los Angeles on 01/08/1999 is actually $500 instead of $300, and we need to update that particular entry. To do so, we use the following SQL:

Sometimes rather than updating, we wish to get rid of records from the table. To do so, we can use the DELETE FROM command. The syntax for this is

DELETE FROM "table_name"WHERE {condition}

It is easiest to use an example. Say we currently have a table as below:

Table Store_Information

and we decide not to keep any information on Los Angeles in this table. We type the following SQL:

Abstract: in this instructional exercise, you will find out about the Oracle DUAL table which is a unique table utilized for assessing articulations or calling functions.

In Oracle, the SELECT proclamation must have a FROM provision. Be that as it may, some queries don’t require any table for example:

SELECT
   UPPER('This is a string')
FROM
   what_table

For this situation, you may consider making a table and utilize it in the FROM statement for simply utilizing the UPPER() work.

Summary: in this tutorial, you will learn how to use the Oracle SELECT statement to query data from a single table.

In Oracle, tables are consists of columns and rows. For example, the customers the table in the sample database has the following columns: customer_id, name, address, website and credit_limit. The  customers the table also has data in these columns.

To retrieve data from one or more columns of a table, you use them SELECT the statement with the following syntax: