Database Reference
In-Depth Information
Input
SELECT note_text
FROM productnotes
WHERE Match(note_text) Against('+safe +(<combination)' IN BOOLEAN MODE);
Analysis
This search matches the words safe and combination , lowering the ranking
of the latter.
Note
Ranked, But Not Sorted In boolean mode, rows will not be returned sorted descending
by ranking score.
Full-Text Search Usage Notes
Before finishing this chapter, here are some important notes pertaining to the
use of full-text searching:
When indexing full-text data, short words are ignored and are
excluded from the index. Short words are defined as those having
three or fewer characters (this number can be changed if needed).
MariaDB comes with a built-in list of stopwords , words that are always
ignored when indexing full-text data. This list can be overridden
if needed. (Refer to the MariaDB documentation to learn how to
accomplish this.)
Many words appear so frequently that searching on them would be
useless (too many results would be returned). As such, MariaDB hon-
ors a 50% rule—if a word appears in 50% or more of the rows, it is
treated as a stopword and is effectively ignored. (The 50% rule is not
used for IN BOOLEAN MODE ).
Full-text searching never returns any results if there are fewer than
three rows in a table (because every word is always in at least 50% of
the rows).
Single quote characters in words are ignored. For example, don't is
indexed as dont .
Languages that don't have word delimiters (including Japanese and
Chinese) will not return full-text results properly.
As already noted, full-text searching is not supported in all database
engines (it is supported in ARIA and MyISAM).
 
 
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