Hi, In mysql i m selecting from a table shouts having a foreign key to another table named "roleuser" with the matching column as user_id Now the user_id column in the shouts table for some rows is null (not actually null but with no inserts in mysql) How to show all the rows of the shouts table either with user_id null or not I m ...
I've searched everywhere for this, but I can't seem to find a solution. Perhaps I'm using the wrong terms. Either way, I'm turning to good ol' trusty S.O. to help my find the answer. I have two tables, we'll call them 'tools' and 'installs' tools = id, name, version installs = id, tool_id, user_id The 'tools' table records available ...
Hi, I'm trying to build a navigation system using categories table with hierarchies. Normally, the table would be defined as follows: id (int) - Primary key name (varchar) - Name of the Category parentid (int) - Parent ID of this Category referenced to same table (Self Join) But the catch is that I require that a category can be child...
HI I am looking for some help I just can't seem to get my head how self joins work. I have this sql code select Persno'Name',convert(char(20), A_Date , 13)'Logins',acode from atrail as LOGIN where acode = 'LOGIN' OR acode = 'LOGOUT' order by a_date desc Which produces a list of User names and when the have logged in and out. What ...
How many joins allowed in SQL Server 2008? ...
I am an old-school MySQL user and always preferred JOIN over sub-query. But nowadays everyone uses sub-query and I hate it, dunno why. Though I've lack of theoretical knowledge to judge myself if there are any difference. Well, I am curious if sub-query as good as join and there is no thing to worry about? ...
I have a query that does what i want joining table but i need it to change sligtly so i can use it for something else. I need to get the last 5 records so i should be using the max function and limit it to 5 but it's not working properly This is my current query, just need to get the last 5 records (probably by the festivalid) SELECT...
I have this query: SELECT COUNT(articles.id) AS count FROM articles, xml_documents, streams WHERE articles.xml_document_id = xml_documents.id AND xml_documents.stream_id = streams.id AND articles.published_at BETWEEN '2010-01-01' AND '2010-04-01' AND streams.brand_id = 7 Which just uses the default equajoin by specifying three tabl...
I think this is a moderately neophyte question. I've been using NHibernate/FluentNHibernate for about 6 months or so, and I think I have a fair grasp of the basics. Now I'm pushing a little bit beyond. I'm sure this is documented, but I've spent several hours now on Google, and haven't quite figured it out. I have simple class, call it...
So, I want to know if to make a Hash Join between two tables is necessary to make a full table scan on the collumns? If i want to join COL1 wiht COL2, and COL1 is smaller, the It makes a full scan in COL1 creating a Hashmap then makes a full scan in COL2 using the sabe hash function. Is this correct? ...
Hi everyone... Consider i am using join on three tables to get a desired result-set... Now in that result set, is there anyway that i can find out which row comes from which table...? Update : I see that i have phrased the question rather wrongly.... As pointed in one of the answers below, a result-set returned by join may will c...
SELECT * FROM TableA INNER JOIN TableB ON TableA.name = TableB.name SELECT * FROM TableA, TableB where TableA.name = TableB.name Which is the preferred way and why? Will there be any performance difference when keywords like JOIN is used? Thanks ...
i have used joins to get datas from two tables under comman name. as SELECT userValidity.UserName, userValidity.ValidFrom,userValidity.ValidUpTo,userValidity.TotalPoints, persons.SenderID FROM userValidity INNER JOIN persons ON userValidity.Username=tbl_persons.Username but i need to execute this query with oly the username which i p...
I have a table with typical statistics on page view and emails. An email creates a row and page view creates a row... I want to chart the page views and emails on a daily basis for the past 30 days (for example) so I need to show the day and the value... even if it ZERO. I cannot have missing days from my results or the chart breaks. ...
I have 2 tables that look like this: Table "public.phone_lists" Column | Type | Modifiers ----------+-------------------+-------------------------------------------------------------------- id | integer | not null default nextval(('"phone_list...
I'm trying to behave. So, instead of using following SQL syntax: select * from tableA INNER JOIN tableB on tableA.id = tableB.tableA_id LEFT OUTER JOIN ( tableC INNER JOIN tableD on tableC.tableD_id = tableD.id) on tableC.tableA_id = tableA.id I'd like to use the CakePHP model->find(). This will let me use the P...
if you compare all the Joins that we have in MySQL, which takes the shortest time to get executed... PLease let me know if the question holds grounds and that if I m right in asking this.. ...
I have a table ('sales') in a MYSQL DB which should rightfully have had a unique constraint enforced to prevent duplicates. To first remove the dupes and set the constraint is proving a bit tricky. Table structure (simplified): 'id (unique, autoinc)' product_id The goal is to enforce uniqueness for product_id. The de-duping policy ...
Does an SQL Server "join" preserve any kind of row order consistently (i.e. that of the left table or that of the right table)? Psuedocode: create table #p (personid bigint); foreach (id in personid_list) insert into #p (personid) values (id) select id from users inner join #p on users.personid = #p.id Suppose I have a list of ID...
SELECT * from `employees` a LEFT JOIN (SELECT phone1 p1, count(*) c, FROM `employees` GROUP BY phone1) b ON a.phone1 = b.p1; I'm not sure if it is this query in particular that has the problem. I have been getting terrible performance in general with this database. The table in question has 120,000 rows. I have tried this particular q...