Syntax and example of the UNION clause - Simple Log Service

You can use the UNION clause to combine result sets from multiple SELECT statements into a single result set.

Syntax

SELECT key1 FROM logstore1
UNION
SELECT key2 FROM logstore2
UNION
SELECT key3 FROM logstore3

Important

Each SELECT statement in a UNION clause must have the same number of columns, and the corresponding columns must have the same data type.

Parameters

Parameter

Description

key

The field name or column name.

The names of key1, key2, and key3 can be different, but they must have the same data type.

Logstore

The name of the Logstore.

Example

The following example calculates page views (PVs) per status code from two Logstores, website_log and internal-operation_log, and combines the results.

Query and analysis statement

* |
SELECT
  status,
  count(*) AS PV
FROM  website_log
GROUP BY
  status
UNION
SELECT
  status,
  count(*) AS PV
FROM  internal-operation_log
GROUP BY
  status

Query and analysis result: The result contains two columns, status and PV. The 24 records show page view counts for HTTP status codes such as 200, 206, 301, 400, and 401.