SQL statements to prevent data duplication in multiple table queries in thinkphp (must-see) _php Tips

Let's take a look at the following examples:

Table

ID name
1 a
2 b
3 C
4 C
5 B

The library structure is probably like this, this is just a simple example, the actual situation will be much more complicated.

SELECT *, COUNT (distinct name) from table group by name

Results:

ID Name count (distinct name)
1 a 1
2 B 1
3 C 1

The last one is superfluous, so don't worry about it.

tp2.0 Manual Search consistent operation to see the relevant information

SELECT cat_id, COUNT (*) as Goods_num from Talble GROUP by cat_id

$M = M (' table ');
$rs = $M->field (Array (' cat_id ', ' count (*) ' => ' Goods_num '))->group (' cat_id ')->select ();

echo $M->getlastsql ();
Print_r ($RS);

The above is a small series for you to bring the thinkphp in multiple tables in the query to prevent data duplication of the SQL statement (must look) of the entire content, I hope to help you, a lot of support cloud Habitat Community ~