9+ Sql Substr 使い方 For You

SQL SUBSTRING Function from www.tutorialgateway.org

Introduction

SQL Substr is a powerful function that allows you to extract a portion of a string using the SQL language. In this article, we will explore the many uses of SQL Substr and provide you with tips on how to use it effectively.

What is SQL Substr?

SQL Substr is a function that allows you to extract a portion of a string. The function takes three parameters: the original string, the starting position of the substring, and the length of the substring.

Example:

SELECT SUBSTR('Hello World', 1, 5);

This will return "Hello". It starts at position 1 and extracts a substring of length 5.

Using SQL Substr for Data Manipulation

SQL Substr can be used to manipulate data in a variety of ways. For example, you can use it to extract specific parts of a string, such as a person's first name or last name.

Example:

SELECT SUBSTR('John Smith', 1, 4) AS first_name, SUBSTR('John Smith', 6) AS last_name;

This will return:

first_name | last_name

--------------------

John | Smith

Using SQL Substr for Data Validation

SQL Substr can also be used for data validation. For example, you can use it to check if a string starts with a specific character or set of characters.

Example:

SELECT CASE WHEN SUBSTR('Hello World', 1, 5) ='Hello' THEN 'Valid' ELSE 'Invalid' END AS validation;

This will return "Valid" because the string starts with "Hello".

Using SQL Substr with Other Functions

SQL Substr can also be used in combination with other functions, such as CONCAT, to create more complex queries.

Example:

SELECT CONCAT(SUBSTR('John Smith', 1, 4), '.', SUBSTR('John Smith', 6)) AS email;

This will return "John.Smith". You can use this query to create an email address.

Conclusion

SQL Substr is a powerful function that can be used for data manipulation and validation. By using this function in combination with other SQL functions, you can create complex queries that meet your specific needs. We hope this guide has been helpful in showing you how to use SQL Substr effectively in 2023.