# How to Use WHERE Clause in PostgreSQL

> In PostgreSQL, the WHERE clause is used to filter the results of different statements such as SELECT, DELETE, UPDATE, etc.

In **PostgreSQL** , the **WHERE** clause is used to filter the results of different statements such as SELECT, DELETE, UPDATE, etc. In PostgreSQL, the **WHERE** clause specifies a condition for retrieving the table's record. Within the specified condition, different operators can be used, such as AND, OR, etc. These operators determine the filtration criteria of the **WHERE** clause.

In this post, you will learn different use cases of the **WHERE** clause within the SELECT statement.

 **How to Use WHERE clause in PostgreSQL?**

In **Postgres** , the **WHERE** clause takes a condition and checks it. If the specified condition is true, then the **WHERE** clause will return a specific value or set of values from the targeted table.

Following will be the basic syntax of the **WHERE** clause:
    
    
    SELECT col_1, col_2, ..... col_N  
    FROM tab_name
    WHERE [condition]

Let’s understand the syntax of the WHERE clause step-by-step:

● **SELECT** command will select a single column or a list of columns.

● **FROM** clause specifies a table or list of tables to be targeted.

● **tab_name** is a table to be selected.

● **WHERE** clause takes a condition and checks if it's true or not. It comes after the FROM clause of any statement.

● **condition** represents a single Boolean expression or a combination of several expressions.

 **Example # 1: Select the Players Whose Age is Greater Than 25**

Follow the below-given steps to understand the working of the **WHERE** clause in **PostgreSQL** :

 **Step 1: Describe the Targeted Table Using Select Command**

Let’s execute the SELECT command followed by an asterisk to retrieve all the columns of the “team_member” table:
    
    
    SELECT * FROM team_members;

The above snippet shows that the team_members table has eight players. Some players are above 25, and others are under 25 years.

 **Step 2: Filter Players Above 25 Using WHERE Clause**

Execute the **SELECT** query with the collaboration of the **WHERE** clause to fetch the name of only those players whose age is above 25:
    
    
    SELECT
      player_name, player_age
    FROM
      team_members
    WHERE
      player_age > 25;

Here, we utilized the greater than sign in the **WHERE** clause to fetch the record of only those team_members whose age is greater than 25:

The output verifies that the **WHERE** clause returns the filtered data.

 **Example # 2: Select the Players Whose Age is Equal to 22 or Whose Name is John**

We will use the **OR** operator in the **WHERE** clause to fetch the player's name whose age is equal to 22 or whose name is John:
    
    
    SELECT * FROM team_members
    WHERE player_age = 22 OR player_name = 'John';

The output clarifies that the **WHERE** clause retrieves the filtered data.

 **Example # 3: Select the Players Whose Name is “John” and Whose Age is Greater than 25**

In **PostgreSQL** , the **AND** operator returns true if both the conditions satisfy the specified criteria. In this example, we will use the **AND** operator, which will return the data of only those players who satisfy both conditions:
    
    
    SELECT * FROM team_members
    WHERE player_name = 'John' AND player_age > 25;

This is how you can use the **AND** operator in the **WHERE** clause.

 **Example # 4: Select the Players Whose Name Starts With ‘J’**

In **PostgreSQL** , the **LIKE** operator is used for pattern matching. In this example, we will use the **LIKE** operator with the **WHERE** clause to filter the players whose name starts with the “ **J** ”:
    
    
    SELECT * FROM team_members
    WHERE player_name LIKE 'J%';

As shown in the output, the **WHERE** clause with the aid of the **LIKE** operator fetched only those players whose name starts with the **“J”**.

 **Example # 5: Select the Players Whose Name is Not Equal to John**

In PostgreSQL, **“ <>”** and **“!=”** symbols are used to check the non-equal values:
    
    
    SELECT * FROM team_members
    WHERE player_name != 'John';

This output confirms that the **WHERE** clause fetched all players except “John”.

From the examples, we can conclude that the **WHERE** clause filters the rows returned by the SELECT statement. That’s all you need to know about the Postgres **WHERE** clause.

 **Conclusion**

In PostgreSQL, the **WHERE** clause can be used within different queries/statements such as SELECT, DELETE, UPDATE, etc. The **WHERE** clause filters the results on the basis of different conditions. The condition represents a single Boolean expression or set of multiple Boolean expressions. In PostgreSQL, different operators can be used within the specified condition, such as AND, OR, !=, >, etc. This write-up considered some examples to summarize the basics of the Postgres **WHERE** clause with the SELECT query.

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