计数SQL查询PHP

Question

I want to count for each gallery number of images in it, here's my query:

$req = db_query("SELECT count(*) FROM node,node_file WHERE node.nid = node_file.nid AND nid = ".$value['nid']);

here's the two tables :
node_file:

nid  |fid   |
-------------
  1  |  1   | 
-------------
  1  |  2   |  
-------------
  1  |  3   |
-------------
  2  |  1   |
-------------
  2  |  2   |
-------------
  2  |  3   |

node:

 nid |type  |
-------------
  1  |Gallery1| 
-------------
  2  |gallery2|  

The error : Query : SELECT count(*) FROM node,node_file WHERE node.nid = node_file.nid AND nid = 34 Message : SQLSTATE[23000]: Integrity constraint violation: 1052 Column 'nid' in where clause is ambiguous

Thanks!

Answer 1

Both of your tables have column nid and you are using column in AND clause so you need to specify to which table it belongs.

SELECT 
    count(*)
FROM
    node,
    node_file
WHERE
    node.nid = node_file.nid AND node.nid = 34

OR

SELECT 
    count(*)
FROM
    node,
    node_file
WHERE
    node.nid = node_file.nid AND node_file.nid = 34

Answer 2

用这个

$req = db_query("SELECT count(*) FROM node,node_file WHERE node.nid = node_file.nid AND node.nid = ".$value['nid']);