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SQL Server full-text search is a powerful tool for searching textual data stored in SQL server databases. This subsystem of SQL Server enables users to run complex queries on text data to discover important insights and information. Today, we will explore how to implement and use this handy feature.
Understanding SQL Server Full-Text Search
Full-Text Search in SQL Server lets users and applications run full-text queries against character-based data in SQL Server tables. To utilize this feature, you need to create a Full-Text index on the columns where the search will take place.
Creating a Full-Text Index
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CREATE FULLTEXT CATALOG ftCatalog AS DEFAULT; CREATE FULLTEXT INDEX ON dbo.Documents ( Title Language 1033, Document VARBINARY(MAX) TYPE COLUMN DocumentType ) KEY INDEX PK_Documents ON ftCatalog; |
In the above example, we have created a Full-Text index on the ‘Documents’ table on the columns ‘Title’ and ‘Document’. ‘VARBINARY(MAX)’ is used to define the column that specifies the type of document. Here, ‘PK_Documents’ is the unique index, and ‘ftCatalog’ is the full-text catalog.
Using Full-Text Search
After creating a full-text index, we can now use it to run full-text queries. In the simplest form, we can use the CONTAINS predicate, like so:
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SELECT DocumentTitle, Document FROM dbo.Documents WHERE CONTAINS((DocumentTitle, Document), 'SQL Server'); |
In this example, we are searching for the keyword ‘SQL Server’ in both the DocumentTitle and Document within the Documents table.
Using the FREETEXT predicate
Another way to use Full-Text search is the use of the FREETEXT predicate. It searches for the meanings of words and not just for exact matching words.
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SELECT DocumentTitle, Document FROM dbo.Documents WHERE FREETEXT((DocumentTitle, Document), 'SQL Server'); |
In this code, we’re again searching in ‘DocumentTitle’ and ‘Document’ for ‘SQL Server’. However, the difference now is that FREETEXT will return matches where there are words in the content that have the same meaning as ‘SQL Server’, not just where there are exact matches.
Conclusion
SQL Server Full-Text Search is a powerful, underutilized feature that can add significant value to your applications by enabling more sophisticated search functionalities. With practice and use, you’ll get familiar with more of its functionalities and be able to create more complex queries like searching for phrase or proximity of words.
Keep exploring and happy querying!