inner-join

问题 How I do query like this ? select Distinct Station , Slot , SubSlot, CompID , CompName from DeviceTrace as DT DT.DeviceID = '1339759958' inner join CompList as CL where and DT.CompID = CL.CompID I need to do DT.DeviceID = '1339759958' before I start with the inner join. I work with sql server. 回答1: I find it difficult to believe that it makes any difference. The query optimiser should apply the predicate before the join if it calculates that it is more efficient to do so. The only

问题 I have two tables TableA and TableB which have information I want to retrieve and update concurrently. When I use SELECT TOP 2 SomeFieldA FROM TableA WITH (ROWLOCK , UPDLOCK , READPAST) everything works fine and Process 1 sees, say, rows 1 and 2, while Process 2 sees, say, rows 3 and 4. This is the expected behaviour. Also, when I execute EXEC sp_lock I see only two KEY entries. However, when I change the statement to SELECT TOP 2 SomeFieldA FROM TableA WITH (ROWLOCK , UPDLOCK , READPAST)

问题 I have 2 tables: Table1 and Table2. Both tables have a column named Column2. I want to set all values of Table1.Column1 as NULL for all records that do not exist in Table2. I.e. all records where Table1.Column2 <> Table2.Column2. This is the query I am trying to execute: UPDATE a SET a.Column1 = null FROM Table1 a INNER JOIN Table2 b ON a.Column2 <> b.Column2 I get a "Token Unknown" Dynamic SQL error on "FROM" when I try to execute this query. Any idea what I am doing wrong? I am fairly new

问题 I want to make inner join between two tables Visit table has visit_id target Report table has rep_id visit_id Each visit has many reports ,I want to select all reports with specified visit target I make like this but it donesn't work $db = Zend_Db_Table::getDefaultAdapter(); $select = $db->select(); $rows = $select->from('visits_tb', array('target', 'visit_id')) ->joinInner('report_tb', 'visits_tb.visit_id= report_tb.visit_id', array('visit_id', 'rep_id')) ->where("visits_tb.visit_id=$id");

问题 I'm trying to create a mysql table from the inner join between two other tables. I'm dealing with a database someone creates which has the following tables: sitematrix_sites sitematrix_databases They are related by another table (I don't know why don't use a foreign key) called sitematrix_sites_databases which has the following fields: site_id and database_id . That's how the two tables relate. Now I'm trying to remove that to make my life easier, so I have: mysql> CREATE TABLE result AS

问题 I'm having a serious problem with MySQL (innoDB) 5.0. A very simple SQL query is executed with a very unexpected query plan. The query: SELECT SQL_NO_CACHE mbCategory.* FROM MBCategory mbCategory INNER JOIN ResourcePermission as rp ON rp.primKey = mbCategory.categoryId where mbCategory.groupId = 12345 AND mbCategory.parentCategoryId = 0 limit 20; MBCategory - contains 216583 rows ResourcePermission - contains 3098354 rows. In MBCategory I've multiple indexes (columns order as in index):

问题 Is there a way to inner join two different Excel spreadsheets using VLOOKUP? In SQL, I would do it this way: SELECT id, name FROM Sheet1 INNER JOIN Sheet2 ON Sheet1.id = Sheet2.id; Sheet1: +----+------+ | ID | Name | +----+------+ | 1 | A | | 2 | B | | 3 | C | | 4 | D | +----+------+ Sheet2: +----+-----+ | ID | Age | +----+-----+ | 1 | 20 | | 2 | 21 | | 4 | 22 | +----+-----+ And the result would be: +----+------+ | ID | Name | +----+------+ | 1 | A | | 2 | B | | 4 | D | +----+------+ How can

问题 This question already has answers here : ORA-00979 not a group by expression (8 answers) Closed 5 years ago . I am new to sql, any help is appreciated. I have two tables, employees and jobs . employees contain a variable job_id (multiple employees can have the same job_ID). jobs contain variables job_id and job_title (one job_ID correspond to one job_title, this is the hr schema in oracle if you are interested). I want the query to return: the job_title, job_ID and the number of people who

问题 I mistyped a query today, but it still worked and gave the intended result. I meant to run this query: SELECT e.id FROM employees e JOIN users u ON u.email=e.email WHERE u.id='139840' but I accidentally ran this query SELECT e.id FROM employees e JOIN users u ON u.email=e.email AND u.id='139840' (note the AND instead of WHERE in the last clause) and both returned the correct employee id from the user id. What is the difference between these 2 queries? Does the second form only join members of

问题 I am trying to understand how to create a query to filter out some results based on an inner join. Consider the following data: formulation_batch ----- id project_id name 1 1 F1.1 2 1 F1.2 3 1 F1.3 4 1 F1.all formulation_batch_component ----- id formulation_batch_id component_id 1 1 1 2 2 2 3 3 3 4 4 1 5 4 2 6 4 3 7 4 4 I would like to select all formulation_batch records with a project_id of 1, and has a formulation_batch_component with a component_id of 1 or 2. So I run the following query: