subquery

问题 I have two fields 'company' and 'url'. I want to sort it by number of times distinct 'company' is occurring and then display three 'url' corresponding to that particular company. Data is stored like this: { "_id" : ObjectId("56c4f73664af6f7305f3670f"), "title" : "Full Stack Software Developer", "url" : "http://www.indeed.com/cmp/Upside-Commerce,-Inc./jobs/Full-Stack-Software-Developer-6e93e36ea5d0e57e?sjdu=QwrRXKrqZ3CNX5W-O9jEvRQls7y2xdBHzhqWkvhd5FFfs8wS9wesfMWXjNNFaUXen2pO-kyc_Qbr7-

问题 Im trying to do a subquery with $this->db->where(" EXISTS (SELECT * FROM myTable)"); But it doesnt work, the output of this is: myquery + WHERE 'EXISTS (SELECT * FROM myTable); That quote before the EXISTS makes the query unresolvable! Does anyone knows how to solve it? Thanks! 回答1: please remove space before and after EXISTS keyword.that does not display any error. $this->db->where("EXISTS(SELECT * FROM myTable)"); 回答2: Maybe you could try to set the escape to false by using $this->db->where

问题 Im trying to do a subquery with $this->db->where(" EXISTS (SELECT * FROM myTable)"); But it doesnt work, the output of this is: myquery + WHERE 'EXISTS (SELECT * FROM myTable); That quote before the EXISTS makes the query unresolvable! Does anyone knows how to solve it? Thanks! 回答1: please remove space before and after EXISTS keyword.that does not display any error. $this->db->where("EXISTS(SELECT * FROM myTable)"); 回答2: Maybe you could try to set the escape to false by using $this->db->where

问题 This is going to be tough to explain. I'm looping through my client records from tbl_customers several times a day. SELECT c.* FROM tbl_customers c I'm returning simply the customer's: customerid , name , phone , email Now the weird part. I want to append 3 more columns, after email: totalpaid, totalowed, totalbalance BUT, Those column names don't exist anywhere. Here is how I query each one: (as a single query) SELECT SUM(total) AS totalpaid FROM tbl_customers_bills WHERE customerid = X AND

问题 I have this query SELECT shot.hole AS hole, shot.id AS id, (SELECT s.id FROM shot AS s WHERE s.hole = shot.hole AND s.shot_number > shot.shot_number AND shot.round_id = s.round_id ORDER BY s.shot_number ASC LIMIT 1) AS next_shot_id, shot.distance AS distance_remaining, shot.type AS hit_type, shot.area AS onto FROM shot JOIN course ON shot.course_id = course.id JOIN round ON shot.round_id = round.id WHERE round.uID = 78 This returns 900~ rows in around 0.7 seconds. This is OK-ish, but there

问题 I am trying to create an implicit rank in the output from the query. The problem seems to be that row_number() is running before worth is calculated. SELECT firstname, lastname, personid, year, ( SELECT COALESCE(SUM(thevalue),0) FROM assets WHERE personidref = w.personid AND year = w.year ) AS assets , ( SELECT COALESCE(SUM(amount),0) FROM liabilities WHERE personidref = w.personid AND year = w.year ) AS liabilities, ( (SELECT COALESCE(SUM(thevalue),0) FROM assets WHERE personidref = w

问题 I now have my JasperReports working from my JRBeancollectionDataSource in my code! I am just a bit confused about some things... When I am designing reports in iRepor t, I create the fields from a query, which I can do fine and all, since when I am actually running the query I'm using a a code JRBeanCollectionDataSource and so is the hql in the report totally irrelevant at this point? Also, I have List collections of other persistent objects in the ones I'm fetching for the report and I want

问题 I'm trying to use this query: SELECT COUNT(PF.PageID) AS Total,P.PageID FROM Pages P LEFT JOIN Pages_Filters PF ON PF.PageID=P.PageID WHERE P.PageID IN ( (SELECT PageID FROM Pages_Filters WHERE FilterID="1" AND FilterOptionID="2" ), (SELECT PageID FROM Pages_Filters WHERE FilterID="7" AND FilterOptionID="57" ) ) AND P.PageID !="283" GROUP BY PF.PageID Which produces the error: Sub-query returns more than 1 row I'd like for MySQL to merge the results of all the sub-queries, and use values in

问题 I'm wondering if there is a general SQL syntax allowing for selecting unaliased numeric literals from sub-selects: -- Seems to work in MySQL / Oracle select table_alias."1" from ( select 1 from dual ) table_alias I know I could alias the fields in the subselect: -- Works everywhere select table_alias.column_alias from ( select 1 column_alias from dual ) table_alias But what if I don't have control over the subselect? Also, some RDBMS allow to provide both table AND column aliases when

问题 Perhaps it's my naiveté, perhaps my paranoia, but I think I'm looking for a solution to a race-condition issue that seems like it should be so common there'd be floods of solutions and I'd've found one by now... but I haven't. The simplistic scenario is I have a process that's supposed to grab any records where there are more than one of a certain type. I'd like to make the system/process(es) thread-/multiprocessing-/reentrant-/buzzword-of-the-day-safe; if the same process gets started and