MySQL 5.7 find_in_set | More on

Read the article to learn more on the MySQL 5.7 FIND_IN_SET() Function. At Bobcares, with our MySQL Support Service, we can handle your issues.

Overview

1. Understanding the MySQL 5.7 FIND_IN_SET() Function
2. Key Features of FIND_IN_SET()
3. Examples
4. Advanced Use Cases
5. Limitations
6. Applications
7. Conclusion

Understanding the MySQL 5.7 FIND_IN_SET() Function

The FIND_IN_SET() function in MySQL is a powerful and efficient tool for searching within comma-separated lists of strings. Whether we’re dealing with tags, categories, or other data stored in such a format, this function simplifies locating specific values in the database.

Key Features of FIND_IN_SET()

Purpose:

Finds the position of a string within a comma-separated list.

Returns the position (index) starting from 1.

Also, returns 0 if the string is not found.

Returns NULL if any input parameter is NULL.

Syntax:

FIND_IN_SET(string, string_list)

string: The string to search for.

string_list: The comma-separated list of strings to search within.

Behavioral Notes:

If the string_list is an empty string (“”), the result is 0.

The function is case-sensitive.

Examples

Example 1: Basic Search

Find the position of “apple” in the list:

SELECT FIND_IN_SET(‘apple’, ‘banana,orange,apple,grape’) AS position;

Result:

Position = 3

Example 2: String Not Found

Search for a string not in the list:

SELECT FIND_IN_SET(‘pear’, ‘banana,orange,apple,grape’) AS position;

Result:

Position = 0

Example 3: NULL Input

When either parameter is NULL:

SELECT FIND_IN_SET(‘apple’, NULL) AS position;

Result:

Position = NULL

Example 4: Case Sensitivity

Case-sensitive search:

SELECT FIND_IN_SET(‘Apple’, ‘banana,orange,apple,grape’) AS position;

Result:

Position = 0 (No match due to case difference)

Advanced Use Cases

1. Dynamic Filtering in Queries

We can use FIND_IN_SET() in the WHERE clause to filter records based on the presence of a value:

SELECT *
FROM products
WHERE FIND_IN_SET(‘electronics’, categories);

This query selects all products that belong to the “electronics” category.

2. Using FIND_IN_SET() with GROUP_CONCAT()

While it’s clever, combining FIND_IN_SET() with GROUP_CONCAT() can be cumbersome. For example:

SELECT *
FROM report_user_foundation
WHERE NOT FIND_IN_SET(user_id, (
SELECT GROUP_CONCAT(login_user_ids)
FROM report_summary
WHERE statistic_time >= 1606752000000
));

A better alternative uses JOIN or EXISTS for clarity and performance:

SELECT rsf.*
FROM report_user_foundation rsf
LEFT JOIN report_summary rs
ON rsf.user_id = rs.login_user_ids
AND rs.statistic_time >= 1606752000000
WHERE rs.id IS NULL;

3. Case-Insensitive Search

To perform a case-insensitive search, use LOWER() or UPPER():

SELECT FIND_IN_SET(LOWER(‘Apple’), LOWER(‘banana,orange,apple,grape’)) AS position;

Result:

Position = 3

Limitations

Performance Concerns: FIND_IN_SET() is not optimized for large datasets or indexes. Avoid overuse in high-performance scenarios.

Case Sensitivity: Requires manual handling for case-insensitive comparisons.

Data Format Dependency: Works only with properly formatted comma-separated lists.

Applications

Position Identification: Determine the index of a value in a list.

Filtering Data: Filter results dynamically based on list membership.

Data Validation: Check if a value exists in a predefined list.

Conditional Updates: Update records conditionally based on list membership.

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Conclusion

The FIND_IN_SET() function is an essential tool for managing and querying comma-separated data in MySQL. Its simplicity and versatility make it valuable for many use cases, but it’s important to consider its limitations, particularly in performance-critical applications. For optimal results, ensure the data is clean and properly formatted before using this function.