MySQL查询返回的行比预期的多，我如何仅从每个组返回一列的最大值？

Question

This query needs to return all rows with the highest value of 'revision' column out of each group of 'sheet_ID' column. It works fine when i do not do the OR statement but i need to be able to use them. The input field is for 'Item Numbers' and the or statement needs to pull that number from a possible of 10 columns where it can be.

Here is my Query statement:

SELECT item_no, item_no1, item_no2, item_no3, item_no4, item_no5, item_no6,
       item_no7, item_no8, item_no9, style, vendor_code, pgc, buyer, brand,
       product_name, sheet_ID, revision, id
FROM product_sheets
WHERE item_no LIKE '$value' or item_no1 LIKE '$value' or
      item_no2 LIKE '$value' or item_no3 LIKE '$value' or
      item_no4 LIKE '$value' or item_no5 LIKE '$value' or 
      item_no6 LIKE '$value' or item_no7 LIKE '$value' or
      item_no8 LIKE '$value' or item_no9 LIKE '$value' AND
      revision IN (SELECT MAX(revision)
                   FROM product_sheets
                   GROUP BY sheet_ID
                  );

Answer 1

Instead of this:

 revision IN (SELECT MAX(revision)
               FROM product_sheets
               GROUP BY sheet_ID
              );

You want a correlated subquery. In your case, you can write it as:

 revision = (SELECT MAX(ps2.revision)
              FROM product_sheets ps2
              WHERE ps2.sheet_ID = product_sheets.sheet_ID
             );

However, I would strongly advise you to use a table alias in the outer query.

You also need to fix the parentheses in the where :

WHERE (item_no LIKE '$value' or item_no1 LIKE '$value' or
       item_no2 LIKE '$value' or item_no3 LIKE '$value' or
       item_no4 LIKE '$value' or item_no5 LIKE '$value' or 
       item_no6 LIKE '$value' or item_no7 LIKE '$value' or
       item_no8 LIKE '$value' or item_no9 LIKE '$value'
      ) AND
      revision = (SELECT MAX(ps2.revision)
                  FROM product_sheets ps2
                  WHERE ps2.sheet_ID = product_sheets.sheet_ID
                 );

If $value doesn't use wildcards, this is much more simply written as:

where '$value' in (item_no, item_no1, item_no2, . . .) and
      revision = (SELECT MAX(ps2.revision)
                  FROM product_sheets ps2
                  WHERE ps2.sheet_ID = product_sheets.sheet_ID
                 );

And, in addition to the comment about normalization (which is strongly suggested), you also need to learn about using query parameters to pass in values to a query.

Answer 2

You must use brackets around th or conditions, without them only the last condition item_no9 LIKE '$value' is related with an AND operator to the IN condition.

WHERE (item_no LIKE '$value' or item_no1 LIKE '$value' or
      item_no2 LIKE '$value' or item_no3 LIKE '$value' or
      item_no4 LIKE '$value' or item_no5 LIKE '$value' or 
      item_no6 LIKE '$value' or item_no7 LIKE '$value' or
      item_no8 LIKE '$value' or item_no9 LIKE '$value'
      )

In addition change the IN condition to the following.
You don't want a revision that is not the max revision of of its sheet_ID to match with a max revision of another sheet_ID.

      AND (sheet_ID,revision) IN (SELECT sheet_ID,MAX(revision)
                                  FROM product_sheets
                                  GROUP BY sheet_ID
                                  );