EXISTS clause - Simple Log Service - Alibaba Cloud Documentation Center

An EXISTS clause is used to check whether a subquery returns a specific result. If the subquery in an EXISTS clause returns a specific result, true is returned and the outer SQL statement is executed.

Syntax

SELECT...FROM...WHERE EXISTS (subquery)

Parameters

Parameter	Description
subquery	The value of this parameter is a SELECT statement.

Example

Check whether the read and write latency of a specific Logstore is greater than 1,000 microseconds. If the latency is greater than 1,000 microseconds, the information of the related consumer group is returned.

Query statement

* |
SELECT
  consumer_group
FROM  "internal-diagnostic_log"
WHERE
  EXISTS (
    SELECT
     Latency
    FROM     internal-operation_log
    WHERE
      "internal-diagnostic_log".LogStore = "internal-operation_log".logstore and latency >1000
  )

Query and analysis result