correlated-subquery | 易学教程

MySQL/SQL: Update with correlated subquery from the updated table itself

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I have a generic question that I will try to explain using an example. Say I have a table with the fields: "id", "name", "category", "appearances" and "ratio" The idea is that I have several items, each related to a single category and "appears" several times. The ratio field should include the percentage of each item's appearances out of the total number of appearances of items in the category. In pseudo-code what I need is the following: For each category find the total sum of appearances for items related to it. For example it can be done with ( select sum("appearances") from table group by

JPA Criteria select all instances with max values in their groups

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问题 Is there a way to write with JPA 2 CriteriaBuilder the equivalent of the following query? select * from season s1 where end = ( select max(end) from season s2 where s1.contest_id=s2.contest_id ); In JPQL this query is: Select s1 from Season s1 where s1.end = ( select max(s2.end) from Season s2 where s1.contest=s2.contest ) 回答1: This should work, with contest being either a basic Integer property, or a ManyToOne property pointing to another non-basic Entity. EntityManger em; //to be injected

Difference between Subquery and Correlated Subquery

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Is the following piece of SQL Query a normal query or a Correlated Subquery ?? SELECT UserID, FirstName, LastName, DOB, GFName, GLName, LoginName, LoginEffectiveDate, LoginExpiryDate, Password, Email, ReportingTo, Mobile, CommunicationPreference, IsActive FROM (SELECT row_number() OVER (ORDER BY FirstName) AS Row, UserID, FirstName, LastName, DOB, GFName, GLName, LoginName, LoginEffectiveDate, LoginExpiryDate, Password, Email, ReportingTo, Mobile, CommunicationPreference, IsActive FROM DivakarUserRegistration) T Also, can someone state the difference between the both Alex Correlated Subquery

Find All Rows With Null Value(s) in Any Column

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问题 I'm trying to create a query that will return all the rows that have a null value across all but 1 column. Some rows will have more than one null entry somewhere. There is one column I will want to exclude, because at this moment in time all of the entries are null and it is the only column that is allowed to have null values. I am stuck because I don't know how to include all of the columns in the WHERE. SELECT * FROM Analytics WHERE * IS NULL Alternatively, I can do a count for one column,

SQLAlchemy Correlated Update with Multiple Columns?

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问题 This question has been asked multiple times on stackoverflow, but they all appeared to be over a year old so I figured I would ask again in case there has been an update. A correlated update is an update statement that updates all rows in one table based on values from another table, while linking the two tables together. From the SQLAlchemy docs, we can do a correlated update easily but only on a single column: update(foo).values(bar=select([foobar.c.bar]).where(foobar.c.id == foo.c.id))

MySQL/SQL: Update with correlated subquery from the updated table itself

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问题 I have a generic question that I will try to explain using an example. Say I have a table with the fields: \"id\", \"name\", \"category\", \"appearances\" and \"ratio\" The idea is that I have several items, each related to a single category and \"appears\" several times. The ratio field should include the percentage of each item\'s appearances out of the total number of appearances of items in the category. In pseudo-code what I need is the following: For each category find the total sum of

Difference between Subquery and Correlated Subquery

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问题 Is the following piece of SQL Query a normal query or a Correlated Subquery ?? SELECT UserID, FirstName, LastName, DOB, GFName, GLName, LoginName, LoginEffectiveDate, LoginExpiryDate, Password, Email, ReportingTo, Mobile, CommunicationPreference, IsActive FROM (SELECT row_number() OVER (ORDER BY FirstName) AS Row, UserID, FirstName, LastName, DOB, GFName, GLName, LoginName, LoginEffectiveDate, LoginExpiryDate, Password, Email, ReportingTo, Mobile, CommunicationPreference, IsActive FROM

SQL update from one Table to another based on a ID match IN db2

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问题 The Query below is suited in SQL sErver. But in DB2 it does not give results: Error is SQLCODE = -199, ERROR: ILLEGAL USE OF KEYWORD FROM. Query: UPDATE Sales_Import SET Sales_Import.AccountNumber = RAN.AccountNumber FROM Sales_Import SI INNER JOIN RetrieveAccountNumber RAN ON SI.LeadID = RAN.LeadID Can someone please clarify the differences b/w DB2 and SQL queries. 回答1: I'm pretty sure (although I've not used DB2 in a while) that DB2 still does not support joins in update statements, so you