postgresql Postgresql全文搜索部分单词
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Postgresql full text search part of words
提问by Grezly
Is postresql capable of doing a full text search, based on 'half' a word?
For example I'm trying to seach for "tree", but I tell postgres to search for "tr".
postresql 是否能够基于“半”字进行全文搜索？例如，我正在尝试"tree"搜索 ，但我告诉 postgres 搜索"tr".
I can't find such a solution that is capable of doing this.
我找不到能够做到这一点的解决方案。
Currently I'm using
目前我正在使用
select * from test, to_tsquery('tree') as q where vectors @@ q ;
But I'd like to do something like this:
但我想做这样的事情：
select * from test, to_tsquery('tr%') as q where vectors @@ q ;
采纳答案by catchdave
Sounds like you simply want wildcard matching.
听起来您只是想要通配符匹配。
One option, as previously mentioned is trigrams. My (very) limited experience with it was that it was too slow on massive tables for my liking (some cases slower than a LIKE). As I said, my experience with trigrams is limited, so I might have just been using it wrong.
A second option you could use is the wildspeedmodule: http://www.sai.msu.su/~megera/wiki/wildspeed(you'll have to build & install this tho).
如前所述，一种选择是trigrams。我对它的（非常）有限的经验是它在我喜欢的大表上太慢了（在某些情况下比 LIKE 慢）。正如我所说，我对三元组的经验有限，所以我可能只是用错了它。
您可以使用的第二个选项是wildspeed模块：http: //www.sai.msu.su/~megera/wiki/wildspeed（您必须构建和安装此 tho）。
The 2nd option will work for suffix/middle matching as well. Which may or may not be more than you're looking for.
第二个选项也适用于后缀/中间匹配。这可能会或可能不会超过您正在寻找的。
There are a couple of caveats (like size of the index), so read through that page thoroughly.
有几个注意事项（例如索引的大小），因此请仔细阅读该页面。
回答by Magnus Hagander
You can use tsearch prefix matching, see http://www.postgresql.org/docs/9.0/interactive/textsearch-controls.html#TEXTSEARCH-PARSING-QUERIES
您可以使用 tsearch 前缀匹配，参见http://www.postgresql.org/docs/9.0/interactive/textsearch-controls.html#TEXTSEARCH-PARSING-QUERIES
postgres=# select to_tsvector('tree') @@ to_tsquery('tr:*');
?column?
----------
t
(1 row)
It will only work for prefix search though, not if you want partial match at any position in the word.
不过，它仅适用于前缀搜索，如果您想在单词中的任何位置进行部分匹配，则无效。
回答by Lecky Lao
select * from test, to_tsquery('tree') as q where vectors @@ q OR xxxx LIKE ('%tree%')
select * from test, to_tsquery('tree') as q where 向量@@ q OR xxxx LIKE ('%tree%')
':*' is to specify prefix matching.
':*' 是指定前缀匹配。
回答by Wolph
It can be done with trigrams but it's not part of tsearch2.
它可以用三元组来完成，但它不是 tsearch2 的一部分。
You can view the manual here: http://www.postgresql.org/docs/9.0/interactive/pgtrgm.html
您可以在此处查看手册：http: //www.postgresql.org/docs/9.0/interactive/pgtrgm.html
Basically what the pg_tgrmmodule does is split a word in all it's parts so it can search for those separate parts.
基本上，该pg_tgrm模块所做的就是将一个单词拆分成它的所有部分，以便它可以搜索这些单独的部分。
