Question

我一直在尝试计算以下几天。请帮助

PostgreSQL表：位置

Id         State

--------------------
1          New York

2          Texas

input ='德克萨斯州对所有牛仔队的问候

输出：包含Texas的行

SELECT id, state FROM locations WHERE state ~* substring(input from state)

Answer 1

1

select * from locations where 'Greetings from Texas to all Cowboys' ~ State;

2

select * from locations where State = any(string_to_array('Greetings from Texas to all Cowboys',' '));

上述两种方法在某些情况下都存在一些问题。但我想知道它们是否适合你。

3

select * from locations where 'reetings from Texas to all Cowboys' ~* ('\\m' || state || '\\M');

最后一种方法会更好。

Answer 2

搜索词不是模式。试试这个：

select * from locations where 'Hello from Texas!' like '%' || state || '%';

或者这个：

select * from locations where 'Hello from Texas!' ~* ('.*' || state || '.*');

如果你想要Posix正则表达式。

示例：

# create table locations(id integer, state text);
CREATE TABLE
# insert into locations values  (1,'New York'),(2,'Texas') ;
INSERT 0 2
# select * from locations where 'Hello from Texas!' like '%' || state || '%';
 id | state
----+-------
  2 | Texas
(1 row)

# select * from locations where 'Hello from Texas!' ~* ('.*' || state || '.*');
 id | state
----+-------
  2 | Texas
(1 row)

# select * from locations where 'Greetings from you ex' like '%' || state || '%';
 id | state
----+-------
(0 rows)

# select * from locations where 'Greetings from your ex' ~* ('.*' || state || '.*');
 id | state
----+-------
(0 rows)

如果您需要检测字边界，这需要一些改进或过程：

# select * from locations where 'fakulos greekos metexas' ~* ('.*' || state || '.*');
id | state
----+-------
2 | Texas

如果您在搜索词中有正则表达式元字符（请参阅PostgresSQL文档作为列表），那么您可能需要先引用它们。这看起来有点奇怪，但这就是逃避总是看起来像：

select regexp_replace('Dont mess (with) Texas, The Lone *',E'([\(\)\*])',E'\\\\\\1','g');

([\(\)\*])是您要转义的字符列表。

但是，如果从不在搜索词中需要正则表达式，那么使用简单的字符串搜索功能（如strpos（）可能更容易：

select strpos('Dont mess (with) Texas','Texas')>0;
?column?
--------
t

select strpos('Dont mess (with) Texas','Mars')>0;
?column?
--------
f

如果您需要不区分大小写的比较

，则可以使用upper()

select strpos(upper('Dont mess (with) Texas'),upper('teXas'))>0;
?column?
--------
t

Answer 3

我会看一下全文搜索：

SELECT 
    id, 
    state 
FROM 
    locations 
WHERE  
    to_tsvector('english', 'Greetings from Texas to all Cowboys') @@ plainto_tsquery('english', state);

标准版本从8.3版本开始，在旧版本中，您必须从contrib。

安装tsearch2

http://www.postgresql.org/docs/current/interactive/textsearch.html

Postgres正则表达式子串或regexp_matches的实际示例

3 个答案: