CodeIgniter: how to have brackets in a JOIN condition

问题

SELECT field1, field2
FROM table1
JOIN table2 ON (table2.field1=table1.field1 OR table2.field2=table1.field2)

How to write this query in CodeIgniter? I want to have brackets in the JOIN condition.

CodeIgniter sample

$this->db->select("field1,field2")
$this->db->from("table1")
$this->db->join("table2","(table2.field1=table1.field1 or table2.field2=table1.field2)")

But this generates an error.

回答1:

I would go with the query() function and write normal SQL.

Like this:

$this->db->query(
   'SELECT field1, field2 
    FROM table1
    JOIN table2 
        ON table2.field1=table1.field1 
        OR table2.field2=table1.field2');

Makes it much more readable. In large applications we frequently have all the queries checked by experts or none CI-programmers, which is impossible when using active-record notation.

You can then even put the queries in seperate files, for better abstraction and cross-team accessibility.

The brackets are not neccessary.

来源：https://stackoverflow.com/questions/11913343/codeigniter-how-to-have-brackets-in-a-join-condition