---
title: "How to check if a string contains letters only in SQL?"  
description: "How to check if a string contains letters only in SQL?"  
author: "Sandra Emily"  
published: 2023-07-30  
updated: 2023-07-31  
canonical: https://www.mindstick.com/forum/159365/how-to-check-if-a-string-contains-letters-only-in-sql  
category: "mssql server"  
tags: ["mssql server", "sql server", "sql"]  
reading_time: 2 minutes  

---

# How to check if a string contains letters only in SQL?

How to [check if](https://www.mindstick.com/forum/12878/how-to-check-if-an-asp-dot-net-file-upload-control-has-a-file-in-jquery) a [string contains](https://www.mindstick.com/forum/12708/how-to-check-a-string-contains-another-string) letters only in [SQL](https://www.mindstick.com/articles/13115/types-of-keys-in-sql-or-oracle-database)?

## Replies

### Reply by Aryan Kumar

Sure, there are a few ways to [check](https://yourviews.mindstick.com/story/2248/never-forget-to-check-these-specifications-before-buying-a-mobile-phone) if strings contain letters only in SQL. Here are some examples:

Using the `REGEXP_LIKE()` function:

SQL

```plaintext
SELECT
  string,
  REGEXP_LIKE(string, '[a-zA-Z]+') AS is_letters_only
FROM
  my_table;
```

The `REGEXP_LIKE()` function takes two arguments: the [string](https://www.mindstick.com/articles/1527/string-split-in-c-sharp) that you want to test and the regular expression that you want to use to test the string. The regular expression in this example matches any string that consists of only letters.

If the string matches the regular expression, the `REGEXP_LIKE()` function returns `TRUE`. Otherwise, it returns `FALSE`.

Using the `CHARINDEX()` function:

SQL

```plaintext
SELECT
  string,
  CHARINDEX('[^a-zA-Z]', string) AS is_letters_only
FROM
  my_table;
```

The `CHARINDEX()` function takes two arguments: the character that you want to find and the string that you want to search. The `CHARINDEX()` function returns the position of the character in the string, or `0` if the character is not found.

In this example, the `CHARINDEX()` function is used to find the first non-letter character in the string. If the `CHARINDEX()` function returns `0`, then the string only contains letters. Otherwise, the string contains at least one non-letter character.

Using the `LOWER()` function:

SQL

```plaintext
SELECT
  string,
  LOWER(string) = LOWER(REPLACE(string, '[^a-zA-Z]', '')) AS is_letters_only
FROM
  my_table;
```

The `LOWER()` function converts all the characters in a string to lowercase. The `REPLACE()` function replaces all the non-letter characters in a string with empty strings.

In this example, the `LOWER()` function is used to convert the string to lowercase. The `REPLACE()` function is then used to replace all the non-letter characters in the string with empty strings. If the resulting string is the same as the original string, then the string only contains letters. Otherwise, the string contains at least one non-letter character.


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Original Source: https://www.mindstick.com/forum/159365/how-to-check-if-a-string-contains-letters-only-in-sql

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