common-table-expression

问题 I've created a complex process that uses several CTEs (mainly for recursive hierarchical work). On small sample sets of data everything goes as expected but when I apply the code to large sets of data I received unexpected (and wrong) results. I think I've narrowed it done to the CTEs. The recursive CTEs are "fed" data processed in several earlier CTEs, and that seems to be the problem. I set up a sample data set as follows: Four rows with unique data Each row receives a random row number

问题 Currently im working on finding the dpendency order of tables in a database. And im stuck up with peoblem of circular depedency of some tables in database. since some tables are circularly depended im not getting the entire order..... Is there any way to find circular dependent tables in any database in sql server, Other than the database diagrams?? 回答1: You don't really need to buy a tool to find these references. SELECT OBJECT_SCHEMA_NAME(fk1.parent_object_id) + '.' + OBJECT_NAME(fk1.parent

问题 Here is a table with sample data: DECLARE @TestTable TABLE ( ItemID INT, A INT, B INT, Month INT) INSERT INTO @TestTable VALUES (1234, 5, 9, 1) INSERT INTO @TestTable VALUES (1234, 6, 9, 2) INSERT INTO @TestTable VALUES (4321, 5, 11, 1) INSERT INTO @TestTable VALUES (4321, 12, 11, 2) INSERT INTO @TestTable VALUES (1324, 14, 6, 1) INSERT INTO @TestTable VALUES (1324, 5, 6, 2) INSERT INTO @TestTable VALUES (1234, 1, 9, 3) INSERT INTO @TestTable VALUES (1324, 9, 6, 3) Something to note is that

问题 I have a connected set of edges with unique nodes. They are connected using a parent node. Consider the following example code and illustration: CREATE TABLE network ( node integer PRIMARY KEY, parent integer REFERENCES network(node), length numeric NOT NULL ); CREATE INDEX ON network (parent); INSERT INTO network (node, parent, length) VALUES (1, NULL, 1.3), (2, 1, 1.2), (3, 2, 0.9), (4, 3, 1.4), (5, 4, 1.6), (6, 2, 1.5), (7, NULL, 1.0); Visually, two groups of edges can be identified. How

问题 Here's a brain-twister for the SQL guys - can anyone think of a reason why the first of these functions performs fine, and the second one runs dog-slow? Function A - Typically finishes in ~5 ms CREATE FUNCTION dbo.GoodFunction ( @IDs UniqueIntTable READONLY ) RETURNS TABLE AS RETURN SELECT p.ID, p.Node, p.Name, p.Level FROM ( SELECT DISTINCT a.Ancestor AS Node FROM Hierarchy h CROSS APPLY dbo.GetAncestors(h.Node.GetAncestor(1)) a WHERE h.ID IN (SELECT Value FROM @IDs) ) np INNER JOIN

问题 I want to insert my foreign keys in multiple tables after a insert into the main table in one CTE. I can't find the solution so it may well be impossible... see this example: CREATE TABLE test_main (main_id serial NOT NULL, main_name character varying(64) default null); CREATE TABLE test_sub_one (sub_one_id serial NOT NULL,sub_one_main_id integer NOT NULL,sub_one_name character varying(64) default null); CREATE TABLE test_sub_two (sub_two_id serial NOT NULL,sub_two_main_id integer NOT NULL

问题 I'm trying to convert a function in Postgres into a select query which I intend to use as a view. The reason is that I'd like to access it from a client via a select query with a where clause instead of using a parameter as with the function. The table represents a tree (and adjacency list) and is defined as follow: CREATE TABLE tree ( id serial primary key, parent_id int references tree(id) ); INSERT INTO tree (id, parent_id) VALUES (1,null) , (2,1), (3,2), (4,3), (5,3) , (6,5), (7,6), (8,4)

问题 I'm trying to convert a function in Postgres into a select query which I intend to use as a view. The reason is that I'd like to access it from a client via a select query with a where clause instead of using a parameter as with the function. The table represents a tree (and adjacency list) and is defined as follow: CREATE TABLE tree ( id serial primary key, parent_id int references tree(id) ); INSERT INTO tree (id, parent_id) VALUES (1,null) , (2,1), (3,2), (4,3), (5,3) , (6,5), (7,6), (8,4)

问题 I have a table one in which there are various attribute like region product,year,qtr,month,sale. I have to calculate the avg_qtr sale of each product having same region and show their previous avg_qtr sale.I have read about lag but here it is not possible to use as it is not fixed after how many rows it will be repeated. My table structure is like this Region Product Year Qtr Month Sales NORTH P1 2015 1 JAN 1000 NORTH P1 2015 1 FEB 2000 NORTH P1 2015 1 MAR 3000 NORTH P1 2015 2 APR 4000 NORTH

问题 I have a table one in which there are various attribute like region product,year,qtr,month,sale. I have to calculate the avg_qtr sale of each product having same region and show their previous avg_qtr sale.I have read about lag but here it is not possible to use as it is not fixed after how many rows it will be repeated. My table structure is like this Region Product Year Qtr Month Sales NORTH P1 2015 1 JAN 1000 NORTH P1 2015 1 FEB 2000 NORTH P1 2015 1 MAR 3000 NORTH P1 2015 2 APR 4000 NORTH