How to use replace function in sql

The REPLACE function in SQL is used to replace all given substrings with another substring in a text or string. Can be used for basic replacement, conditional replacement, and NULL value handling. The basic syntax is: REPLACE(string, old_substring, new_substring).

Usage of REPLACE function in SQL

The REPLACE function is used to replace all given values ​​in a text or string. A given substring is another substring. It can update data in the database based on specified conditions.

Syntax

<code>REPLACE(string, old_substring, new_substring)</code>

Parameters

• string: Need to replace the substring text or string.
• old_substring: The substring to be replaced from string.
• new_substring: New substring that replaces old_substring.

Usage

1. Basic usage: Replace all occurrences of substrings in a text or string.

<code>SELECT REPLACE('This is a sample text', 'sample', 'example');</code>

Result: This is an example text

2. Conditional replacement: Replace substrings based on given conditions.

<code>SELECT REPLACE('This is a sample text', 'sample', 'example', 1);</code>

Result: This is an example text

where 1 specifies that only the first occurrence of the substring is replaced.

3. NULL value handling: The REPLACE function supports NULL values. If old_substring or new_substring is NULL, NULL is returned.

<code>SELECT REPLACE('This is a sample text', NULL, 'example');</code>

Result: NULL

Notes

##The REPLACE function is case-sensitive.
• If old_substring does not exist in string, no replacement is performed.
• The REPLACE function does not modify the original data. It returns a copy containing the replaced data.

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