![]() Rows from one table refer to specific rows in another table, which are connected by some ID column(s). Relational databases are built with multiple tables that refer to each other. Querying Data From Multiple Tables Using WHERE The query returns the details about a product only If the price of that product is less than 250.00. ![]() In this example, the condition compares the value in the column price to 250.00. At the end of the query, the WHERE keyword is followed by the filtering condition. The columns are listed after the SELECT, then the keyword FROM helps specify the table from which you retrieve data. In this case, the result set consists of only two rows with the columns name and price: name You can also filter rows to return only the records that match the given criteria. Next is the keyword FROM and the name of the table where the data is stored. In this simple query, the names of the columns from which you want to retrieve data are listed after SELECT. To select data from all columns and from all rows in this table, you might use the query: Consider the following table, product: id How to Query a Single Tableįirst, a quick refresher on how to select data from a single table. ![]() It is the most complete practical review of SQL JOINs available on the Internet. The course covers simple 2-table joins, multiple joins, LEFT JOIN, FULL JOIN, self join, any many more. It offers over 90 hands-on exercises on different kinds of JOINs. If you want to practice joining tables in SQL, check out our interactive SQL JOINs course. In this article, you will learn how to join two tables by using WHERE and by using a special operator JOIN, and you will see how to filter rows in the result set. It is not difficult if you know how to use the dedicated SQL operators for doing this. Querying data from multiple tables is very common when working with relational databases.
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