Какое sql ключевое слово используется для указания условного поиска

В SQL для указания условного поиска используется ключевое слово WHERE. Оно позволяет фильтровать результаты запроса с использованием логических выражений.

Пример:

SELECT * FROM table_name
WHERE condition;
    

Здесь table_name - это имя таблицы, а condition - это логическое выражение, определяющее условия поиска.

Understanding SQL: The Keyword for Conditional Search

Welcome to the world of SQL! This powerful language allows us to interact with databases, retrieve information, and perform various operations. One common task in SQL is to search for specific data based on certain conditions. In this article, we will explore the specific SQL keyword used for conditional search, and understand how it works with code examples.

The SELECT Statement

In SQL, the SELECT statement is used to retrieve data from one or more tables in a database. It allows us to specify the fields we want to fetch, the table(s) we want to retrieve data from, and any conditions to filter the data. When it comes to conditional search, we need to use an additional keyword along with the SELECT statement to specify the conditions.

The WHERE Keyword

The keyword used to specify conditional search in SQL is WHERE. The WHERE keyword is followed by a condition or a set of conditions that are used to filter the data. It acts as a filter, allowing us to retrieve only those records that satisfy the specified condition(s).

Let's take a look at an example to see how the WHERE keyword works:

SELECT * FROM employees WHERE salary > 50000;

In this example, we are selecting all the fields from the "employees" table where the salary is greater than 50000. Here, the WHERE keyword is used to specify the condition "salary > 50000". The result will be all the employee records whose salary is greater than 50000.

Using Multiple Conditions

The WHERE keyword can be used with multiple conditions by combining them using logical operators such as AND or OR. This allows us to perform more complex conditional searches. Let's see an example:

SELECT * FROM employees WHERE department = 'IT' AND salary > 50000;

In this example, we are selecting all the fields from the "employees" table where the department is 'IT' AND the salary is greater than 50000. Here, the AND operator is used to combine two conditions. The result will be all the employee records whose department is 'IT' and salary is greater than 50000.

Additional Operators for Conditional Search

Aside from the comparison operators like =, <, >, and !=, SQL provides a set of additional operators that can be used in conditional searches. Some of these operators include:

• LIKE: Used for pattern matching, i.e., when you want to search for records that match a specific pattern.
• IN: Used to check if a value exists in a specified list of values.
• BETWEEN: Used to check if a value is within a specified range of values.
• IS NULL: Used to check for missing or NULL values.

These operators expand the capabilities of conditional searches in SQL, allowing us to perform more specific and targeted searches on the data.

Conclusion

In SQL, the WHERE keyword is used to specify conditional search. It allows us to filter data based on specific conditions and retrieve only the records that satisfy those conditions. By using logical operators and additional operators, we can further refine our searches and retrieve more precise results.

Now that you have a clear understanding of the keyword used for conditional search in SQL, you can start incorporating it in your queries and perform complex searches on your databases. Happy coding!