Cheatsheet voor SQL naar Kusto-querytaal
Als u bekend bent met SQL en meer wilt weten over KQL, vertaalt u SQL-query's naar KQL door de SQL-query vooraf te voorzien van een opmerkingsregel, --
en het trefwoord explain
. De uitvoer toont de KQL-versie van de query, die u kan helpen de syntaxis en concepten van KQL te begrijpen.
--
explain
SELECT COUNT_BIG(*) as C FROM StormEvents
Uitvoer
Query’s uitvoeren |
---|
StormEvents<br> | summarize C=count()<br> | project C |
Cheatsheet voor conversie van SQL naar Kusto
In de volgende tabel ziet u voorbeeldquery's in SQL en de bijbehorende KQL-equivalenten.
Categorie | SQL Query | Kusto-query | Lees meer |
---|---|---|---|
Gegevens uit tabel selecteren | SELECT * FROM dependencies |
dependencies |
Tabellaire expressie-instructies |
-- | SELECT name, resultCode FROM dependencies |
dependencies | project name, resultCode |
Project |
-- | SELECT TOP 100 * FROM dependencies |
dependencies | take 100 |
Nemen |
Null-evaluatie | SELECT * FROM dependencies WHERE resultCode IS NOT NULL |
dependencies | where isnotnull(resultCode) |
isnotnull() |
Vergelijkingsoperatoren (datum) | 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)) |
Tussen |
Vergelijkingsoperatoren (tekenreeks) | SELECT * FROM dependencies WHERE type = "Azure blob" |
dependencies | where type == "Azure blob" |
Logische operators |
-- | -- substring SELECT * FROM dependencies WHERE type like "%blob%" |
// substring dependencies | where type has "blob" |
Hsa |
-- | -- wildcard SELECT * FROM dependencies WHERE type like "Azure%" |
// wildcard dependencies | where type startswith "Azure" // or dependencies | where type matches regex "^Azure.*" |
startswith komt overeen met regex |
Vergelijking (booleaanse waarde) | SELECT * FROM dependencies WHERE !(success) |
dependencies | where success == False |
Logische operators |
Groepering, aggregatie | SELECT name, AVG(duration) FROM dependencies GROUP BY name |
dependencies | summarize avg(duration) by name |
Samenvatten avg() |
Distinct | SELECT DISTINCT name, type FROM dependencies |
dependencies | summarize by name, type |
Samenvatten Verschillende |
-- | 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() |
Kolomaliassen, uitbreiden | SELECT operationName as Name, AVG(duration) as AvgD FROM dependencies GROUP BY name |
dependencies | summarize AvgD = avg(duration) by Name=operationName |
Alias-instructie |
-- | SELECT conference, CONCAT(sessionid, ' ' , session_title) AS session FROM ConferenceSessions |
ConferenceSessions | extend session=strcat(sessionid, " ", session_title) | project conference, session |
strcat() Project |
Ordenen | SELECT name, timestamp FROM dependencies ORDER BY timestamp ASC |
dependencies | project name, timestamp | sort by timestamp asc nulls last |
Sorteren |
Top n op meting | 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 |
Boven |
Union | SELECT * FROM dependencies UNION SELECT * FROM exceptions |
union dependencies, exceptions |
Unie |
-- | SELECT * FROM dependencies WHERE timestamp > ... UNION SELECT * FROM exceptions WHERE timestamp > ... |
dependencies | where timestamp > ago(1d) | union (exceptions | where timestamp > ago(1d)) |
|
Deelnemen | 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 |
Geneste query's | 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 |
Met | SELECT COUNT(\*) FROM dependencies GROUP BY name HAVING COUNT(\*) > 3 |
dependencies | summarize Count = count() by name | where Count > 3 |
Samenvatten Waar |
Gerelateerde inhoud
- T-SQL gebruiken om query's uit te voeren op gegevens
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