Beginner

243. SUBSTRING Function

Learn how to extract a specific portion of text from a string.

📘 Lesson 243 of 728 ⏱ 9 min 🎯 Beginner

The SUBSTRING function extracts a portion of a string based on a starting position and, depending on the database, a specified length.

Many business fields contain useful information embedded inside larger strings. SUBSTRING helps extract that information.

Extract the first three characters of a customer code.

SQL 
SELECT
    CustomerCode,
    SUBSTRING(CustomerCode, 1, 3) AS RegionCode
FROM Customers;

SUBSTRING is useful for parsing identifiers, extracting codes, preparing reporting fields, and cleaning imported data.

  • SUBSTRING extracts part of a string.
  • A starting position is used.
  • A length may also be specified.
  • Position numbering can vary by database.
  • It is useful for parsing text.
What does SUBSTRING do?

SUBSTRING extracts a specified portion of a text value.

Where is SUBSTRING useful?

It is useful for extracting codes, prefixes, identifiers, and other pieces of information from text.

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