Comparing SQL Server Full-Text Search and LIKE
By Tom Nonmacher
When it comes to searching textual data in SQL Server, two options that usually come to mind are Full-Text Search and the LIKE operator. Both are tools that can be used for pattern matching and searching text, but they differ in their approaches and capabilities. In this post, we will compare SQL Server Full-Text Search and the LIKE operator, highlighting their differences and potential use cases.
Full-Text Search is a powerful tool that allows for advanced text queries against character-based data in SQL Server tables. Unlike the LIKE operator, which only supports simple pattern matching using wildcards, Full-Text Search supports complex word and phrase searches, as well as proximity and inflectional searches. This makes it an excellent choice for applications that require sophisticated text queries, such as content management systems or document repositories.
-- Full-Text Search example in SQL Server 2012
SELECT * FROM Posts
WHERE CONTAINS(Title, '"SQL Server" OR "Full-Text Search"')
On the other hand, the LIKE operator is a simple and efficient tool for basic pattern matching. It uses wildcard characters to match any sequence of characters in a string. Although it lacks the advanced text search capabilities of Full-Text Search, the LIKE operator is very efficient for simple text queries and can be used in any SQL Server or SQL-based database, such as MySQL 5.6, DB2 10.5, or Azure SQL.
-- LIKE operator example in MySQL 5.6
SELECT * FROM Posts
WHERE Title LIKE '%SQL Server%'
When it comes to performance, Full-Text Search generally performs better than the LIKE operator for large text-based data sets. This is because Full-Text Search uses a special index called the Full-Text index to store the words in the text data, allowing for faster text queries. However, keep in mind that maintaining a Full-Text index can be resource-intensive and can slow down data modification operations.
In contrast, the LIKE operator does not use any special index, and its performance depends on the size of the text data and the distribution of the data values. For small data sets or fields with a limited number of unique values, the LIKE operator can be very efficient. However, for large text data or fields with many unique values, the LIKE operator can be slow and inefficient.
In conclusion, both SQL Server Full-Text Search and the LIKE operator have their strengths and weaknesses. Full-Text Search is a robust tool for advanced text queries, while the LIKE operator is a simple and versatile tool for basic pattern matching. Depending on your application's requirements, you may choose one over the other, or even use both in combination. Remember to always test different approaches and choose the one that best fits your needs.