Question

I need to update some rows in my table, for simplicity called “three”.

I select the columns to update with this query:

SELECT one.id
FROM one 
    JOIN `two` ON ( one.id = two.page )
    JOIN `three` ON ( one.id = three.item )
WHERE two.level = 1
    AND  two.item = (SELECT item FROM two WHERE page = 5 AND level = 1 ) 
    AND three.position > (SELECT position FROM three WHERE item = 5 ) 
ORDER BY three.position

Now I call an update query with id’s I get.

Is there any chance to eliminate the subqueries?

Edit (after Melanie’s comment):

Table “one”:

|id|text|

Table “two”:

|id|item|page|level|

Table “three”:

|item|position|

So when I run the query

SELECT item FROM two WHERE page = 5 AND level = 1

It will return f.ex 1 and the final WHERE clause will be:

two.item = 1 AND two.level = 1

Which is not the same as:

two.level = 1 and two.page = 5

I have the table one – some text with some one.id. I need to update all items from table three which has higher position than my item (f.ex. id = 5) have. But those items should also have the same two.item in table two, where two.page = one.id and level = 1

I am sorry for a poor description.

Answer 1

You should be able to replace those subqueries by joins:

SELECT one.id
FROM one 
    JOIN `two2` ON (two2.page = 5 AND two2.level = 1)
    JOIN `two` ON ( one.id = two.page AND two.item = two2.item )
    JOIN `three2` ON ( three.item = 5)
    JOIN `three` ON ( one.id = three.item AND three.position > three2.position)
WHERE two.level = 1
ORDER BY three.position