将 SQL 转换为 Kusto 查询语言的速查表
如果你熟悉 SQL 并想要了解 KQL,请将 SQL 查询转换为 KQL,方法是在 SQL 查询前面加上注释行 --
和关键字 explain
。 输出将显示该查询的 KQL 版本,这可以帮助你了解 KQL 语法和概念。
--
explain
SELECT COUNT_BIG(*) as C FROM StormEvents
输出
查询 |
---|
StormEvents<br> | summarize C=count()<br> | project C |
SQL 到 Kusto 备份单
下表显示了以 SQL 编写的示例查询及其 KQL 等效项。
类别 | SQL 查询 | Kusto 查询 | 了解更多 |
---|---|---|---|
从表中选择数据 | SELECT * FROM dependencies |
dependencies |
表格表达式语句 |
-- | SELECT name, resultCode FROM dependencies |
dependencies | project name, resultCode |
project |
-- | SELECT TOP 100 * FROM dependencies |
dependencies | take 100 |
take |
Null 评估 | SELECT * FROM dependencies WHERE resultCode IS NOT NULL |
dependencies | where isnotnull(resultCode) |
isnotnull() |
比较运算符(日期) | 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)) |
between |
比较运算符(字符串) | SELECT * FROM dependencies WHERE type = "Azure blob" |
dependencies | where type == "Azure blob" |
逻辑运算符 |
-- | -- 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 matches regex |
比较(布尔值) | SELECT * FROM dependencies WHERE !(success) |
dependencies | where success == False |
逻辑运算符 |
分组,聚合 | SELECT name, AVG(duration) FROM dependencies GROUP BY name |
dependencies | summarize avg(duration) by name |
summarize avg() |
Distinct | SELECT DISTINCT name, type FROM dependencies |
dependencies | summarize by name, type |
summarize distinct |
-- | 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() |
列别名、扩展 | SELECT operationName as Name, AVG(duration) as AvgD FROM dependencies GROUP BY name |
dependencies | summarize AvgD = avg(duration) by Name=operationName |
Alias 语句 |
-- | SELECT conference, CONCAT(sessionid, ' ' , session_title) AS session FROM ConferenceSessions |
ConferenceSessions | extend session=strcat(sessionid, " ", session_title) | project conference, session |
strcat() project |
中间件排序 | SELECT name, timestamp FROM dependencies ORDER BY timestamp ASC |
dependencies | project name, timestamp | sort by timestamp asc nulls last |
sort |
按度量值排名的前 n 位 | 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 |
返回页首 |
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)) |
|
联接 | 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 |
嵌套查询 | 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 |
summarize where |
相关内容
- 使用 T-SQL 查询数据