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INNER JOIN EXAMPLE POSTGRESQL CODE

1) Using PostgreSQL INNER JOIN to join two tables Let’s take some examples of using the INNER JOIN clause. In practice, you will use table aliases to assign the joined tables short names to make the query more readable. To avoid the error, you need to qualify these columns fully using the following syntax: table_name.

If you reference columns with the same name from different tables in a query, you will get an error. Most of the time, the tables that you want to join will have columns with the same name e.g., id column like customer_id. The following Venn diagram illustrates how INNER JOIN clause works.

In case these values are not equal, the inner join just ignores them and moves to the next row.

If these values are equal, the inner join creates a new row that contains all columns of both tables and adds it to the result set.

Third, specify the second table (table B) in the INNER JOIN clause and provide a join condition after the ON keyword.įor each row in the table A, inner join compares the value in the pka column with the value in the fka column of every row in the table B:.

Second, specify the main table i.e., table A in the FROM clause.

First, specify columns from both tables that you want to select data in the SELECT clause.

To join table A with the table B, you follow these steps:

INNER JOIN EXAMPLE POSTGRESQL CODE

INNER JOIN B ON pka = fka Code language: SQL (Structured Query Language) ( sql ) To select data from both tables, you use the INNER JOIN clause in the SELECT statement as follows: SELECT