SQL per Linguaggio di query Kusto foglio di controllo

  • Articolo

Se si ha familiarità con SQL e si vuole imparare KQL, convertire le query SQL in KQL prefaendo la query SQL con una riga di commento, --e la parola chiave explain. L'output mostra la versione KQL della query, che consente di comprendere la sintassi e i concetti di KQL.

Eseguire la query

--
explain
SELECT COUNT_BIG(*) as C FROM StormEvents

Output

Query
StormEvents<br>| riepilogare C=count()<br>| progetto C

Scheda di riferimento rapido sul passaggio da SQL a Kusto

La tabella seguente illustra le query di esempio in SQL e i relativi equivalenti KQL.

Category Query SQL Query Kusto Altre informazioni
Selezione di dati da una tabella SELECT * FROM dependencies dependencies Istruzioni di espressione tabulare
-- SELECT name, resultCode FROM dependencies dependencies | project name, resultCode project
-- SELECT TOP 100 * FROM dependencies dependencies | take 100 take
Valutazione null SELECT * FROM dependencies
WHERE resultCode IS NOT NULL		 dependencies
| where isnotnull(resultCode)		 isnotnull()
Operatori di confronto (data) SELECT * FROM dependencies
WHERE timestamp > getdate()-1		 dependencies
| where timestamp > ago(1d)		 ago()
-- SELECT * FROM dependencies
WHERE timestamp BETWEEN ... AND ...		 dependencies
| where timestamp between (datetime(2016-10-01) .. datetime(2016-11-01))		 Tra
Operatori di confronto (stringa) SELECT * FROM dependencies
WHERE type = "Azure blob"		 dependencies
| where type == "Azure blob"		 Operatori logici
-- -- substring
SELECT * FROM dependencies
WHERE type like "%blob%"		 // substring
dependencies
| where type has "blob"		 has
-- -- wildcard
SELECT * FROM dependencies
WHERE type like "Azure%"		 // wildcard
dependencies
| where type startswith "Azure"
// or
dependencies
| where type matches regex "^Azure.*"		 startswith
corrisponde a regex
Confronto (booleano) SELECT * FROM dependencies
WHERE !(success)		 dependencies
| where success == False		 Operatori logici
Raggruppamento, aggregazioni SELECT name, AVG(duration) FROM dependencies
GROUP BY name		 dependencies
| summarize avg(duration) by name		 Riassumere
avg()
Distinct SELECT DISTINCT name, type FROM dependencies dependencies
| summarize by name, type		 Riassumere
Distinti
-- SELECT name, COUNT(DISTINCT type)
FROM dependencies
GROUP BY name		 dependencies
| summarize by name, type | summarize count() by name
// or approximate for large sets
dependencies
| summarize dcount(type) by name 		count()
dcount()
Alias di colonna, estensioni SELECT operationName as Name, AVG(duration) as AvgD FROM dependencies
GROUP BY name		 dependencies
| summarize AvgD = avg(duration) by Name=operationName		 Istruzione alias
-- SELECT conference, CONCAT(sessionid, ' ' , session_title) AS session FROM ConferenceSessions ConferenceSessions
| extend session=strcat(sessionid, " ", session_title)
| project conference, session		 strcat()
Progetto
Ordering SELECT name, timestamp FROM dependencies
ORDER BY timestamp ASC		 dependencies
| project name, timestamp
| sort by timestamp asc nulls last		 sort
Primi n in base a misura SELECT TOP 100 name, COUNT(*) as Count FROM dependencies
GROUP BY name
ORDER BY Count DESC		 dependencies
| summarize Count = count() by name
| top 100 by Count desc		 top
Union SELECT * FROM dependencies
UNION
SELECT * FROM exceptions		 union dependencies, exceptions union
-- SELECT * FROM dependencies
WHERE timestamp > ...
UNION
SELECT * FROM exceptions
WHERE timestamp > ...		 dependencies
| where timestamp > ago(1d)
| union
(exceptions
| where timestamp > ago(1d))
Join SELECT * FROM dependencies
LEFT OUTER JOIN exceptions
ON dependencies.operation_Id = exceptions.operation_Id		 dependencies
| join kind = leftouter
(exceptions)
on $left.operation_Id == $right.operation_Id		 join
Query nidificate SELECT * FROM dependencies
WHERE resultCode ==
(SELECT TOP 1 resultCode FROM dependencies
WHERE resultId = 7
ORDER BY timestamp DESC)		 dependencies
| where resultCode == toscalar(
dependencies
| where resultId == 7
| top 1 by timestamp desc
| project resultCode)		 toscalar
Having SELECT COUNT(\*) FROM dependencies
GROUP BY name
HAVING COUNT(\*) > 3		 dependencies
| summarize Count = count() by name
| where Count > 3		 Riassumere
Dove

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