Write a query to list top 5 most expensive categories năm 2024
I’m a big fan of using queries based on the dynamic management view sys.dm_exec_query_stats to identify the most resource hungry queries across a SQL instance. There are lots of versions of this sort of query around the place if you google for “Top 20 queries”. Show That approach has some limitations though. First, it is cleared out every time an instance restarts, and second it only keeps figures for currently cached plans, so when a query recompiles, data is lost. The DMVs provided by SQL Server Query Store solve these issues, as data is persisted in the database over time, so nothing is lost on restarts etc. And one extra thing you gain by using the Query Store DMVs is that you can slice by time interval, for instance if you want to look at the before and after states relating to a change that has been made – or you want to look at an interval where performance degradation has been reported. Some time ago I wrote a query store version of the “Top 20 queries” query that will produce a ranked list of your most expensive queries – and I’ve ended up using this a lot. The only downside of using the DMVs for Query Store is that they are per database whereas dm_exec_query_stats is a view across the whole instance. So I had to use a cursor and a temp table, populating the temp table for each database in turn. Here’s the query: --Gather and report on most resource hungry queries DECLARE @Reportinginterval int; DECLARE @Database sysname; DECLARE @StartDateText varchar(30); DECLARE @TotalExecutions decimal(20,3); DECLARE @TotalDuration decimal(20,3); DECLARE @TotalCPU decimal(20,3); DECLARE @TotalLogicalReads decimal(20,3); DECLARE @SQL varchar(MAX); --Set Reporting interval in days SET @Reportinginterval = 1; SET @StartDateText = CAST(DATEADD(DAY, -@Reportinginterval, GETUTCDATE()) AS varchar(30)); --Cursor to step through the databases DECLARE curDatabases CURSOR FAST_FORWARD FOR SELECT [name] FROM sys.databases WHERE is_query_store_on = 1; --Temp table to store the results DROP TABLE IF EXISTS Stats;CREATE TABLE Stats (DatabaseName sysname, SchemaName sysname NULL, ObjectName sysname NULL, QueryText varchar(1000), TotalExecutions bigint, TotalDuration decimal(20,3), TotalCPU decimal(20,3), TotalLogicalReads bigint ); OPEN curDatabases; FETCH NEXT FROM curDatabases INTO @Database; --Loop through the datbases and gather the stats WHILE @@FETCH_STATUS = 0 BEGIN SET @SQL = ' USE [' + @Database + '] INSERT intO StatsSELECT FROM sys.query_store_query q
INNER JOIN sys.query_store_query_text t INNER JOIN sys.query_store_plan p INNER JOIN sys.query_store_runtime_stats rs INNER JOIN sys.query_store_runtime_stats_interval rsi LEFT JOIN sys.objects o LEFT JOIN sys.schemas s WHERE rsi.start_time > ''' + @StartDateText + '''
GROUP BY s.name, o.name, SUBSTRING(t.query_sql_text,1,1000)
OPTION(RECOMPILE);';
EXEC (@SQL);
FETCH NEXT FROM curDatabases INTO @Database;
END;
CLOSE curDatabases;
DEALLOCATE curDatabases;
--Aggregate some totals
SELECT
@TotalExecutions = SUM(TotalExecutions),
@TotalDuration = SUM (TotalDuration),
@TotalCPU = SUM(TotalCPU),
@TotalLogicalReads = SUM(TotalLogicalReads)
FROM Stats--Produce output SELECT TOP 20 DatabaseName, SchemaName, ObjectName, QueryText, TotalExecutions, CAST((TotalExecutions/@TotalExecutions)*100 AS decimal(5,2)) AS [TotalExecutions %], CAST(TotalDuration/1000000 AS decimal(19,2)) AS [TotalDuration(s)], CAST((TotalDuration/@TotalDuration)*100 AS decimal(5,2)) AS [TotalDuration %], CAST((TotalDuration/TotalExecutions)/1000 AS decimal(19,2)) AS [AverageDuration(ms)], CAST(TotalCPU/1000000 AS decimal(19,2)) [TotalCPU(s)], CAST((TotalCPU/@TotalCPU)*100 AS decimal(5,2)) AS [TotalCPU %], CAST((TotalCPU/TotalExecutions)/1000 AS decimal(19,2)) AS [AverageCPU(ms)], TotalLogicalReads, CAST((TotalLogicalReads/@TotalLogicalReads)*100 AS decimal(5,2)) AS [TotalLogicalReads %], CAST((TotalLogicalReads/TotalExecutions) AS decimal(19,2)) AS [AverageLogicalReads] FROM Stats--Order by the resource you're most interested in --ORDER BY TotalExecutions DESC --ORDER BY TotalDuration DESC ORDER BY TotalCPU DESC --ORDER BY TotalLogicalReads DESC DROP TABLE Stats;The script limits itself to looking at databases where query store is enabled. If you want to bring back more results you can just change the TOP statement, and if you want to look at the results ordered by a different resource (e.g. Reads) then just make sure the relevant ORDER BY clause is uncommented. With other small modifications I find this script useful in a myriad of scenarios. I hope you find it useful too. Related: How does Query Store capture cross database queries? Introduction to SQL Server Query Store Got a problem or embarking on a SQL Server project and want some help and advice? I’m available for consulting – please get in touch or check out my services page to find out what I can do for you. How do I select top 5 in SQL query?Example - Using TOP keyword For example: SELECT TOP(5) contact_id, last_name, first_name FROM contacts WHERE last_name = 'Anderson' ORDER BY contact_id; This SQL SELECT TOP example would select the first 5 records from the contacts table where the last_name is 'Anderson'.nullSQL: SELECT TOP Statement - TechOnTheNetwww.techonthenet.com › sql › select_topnull How to show the most expensive item in SQL?SET @p1 := (SELECT MAX(price) FROM items); SELECT * FROM items WHERE price = @p1; Using variables, p1 stores the maximum price from the table items and then uses the variable p1 in the following query to return all records which have that maximum price without limiting the number of records as you desired.nullmysql - How to find most expensive items in sql with more than one ...stackoverflow.com › questions › how-to-find-most-expensive-items-in-sql-...null How to write a SQL query to find the highest purchase amount?SELECT customer_id, MAX(purch_amt) FROM orders GROUP BY customer_id; Find the highest purchase amount ordered by the each customer on a particular date with their ID, order date and highest purchase amount.nullSQL Practice 1mebrahimii.github.io › comp440-spring2020 › lecture › week_6 › SQL_Pr...null |