Summary

Often in our world of computer-managed precision and rigid logic, it's important to see past exact values and look for information with similar meaning and context. The SOUNDEX() and DIFFERENCE() functions were designed help you make inexact comparisons, matching words with the same or similar phonetic patterns. Using the SOUNDEX() function is actually an older and fairly unsophisticated technique for matching words based on basic phonetic language rules. It's simple and often useful for matching words that sound similar.

Full-text indexing is a very capable resource for searching and matching content within any text, large or small. The CONTAINS and FREETEXT predicates work very effectively where you may be storing very large volumes of notes, comments, or document content. The CONTAINS predicate gives you fairly precise control over matching logic but will also let you find words, text, and phrases that are grammatically similar to the words you search for. The FREETEXT predicate is generally used for soft-matching a phrase when you don't need text to match exactly, but to find text with similar meaning and content. The CONTAINSTABLE and FREETEXTTABLE predicates expand on their base predicates by returning SQL table types capable of presenting a ranked listing of qualifying values and integrating these features into more sophisticated queries.