WITH clause - Simple Log Service - Alibaba Cloud Documentation Center

You can use a WITH clause to save the result of a subquery to a temporary table. Then, you can execute an SQL statement to analyze the data in the temporary table. You can use WITH clauses to simplify SQL statements and improve readability. This topic describes the syntax of WITH clauses and provides examples on how to use WITH clauses.

Syntax

WITH table_name AS (select_statement) select_statement

Parameters

Parameter	Description
table_name	The name of the temporary table.
select_statement	The complete SELECT statement.

Example

Analyze the average request length for each host in a Logstore named website_log and save the analysis result to a table named T1. Analyze the average request length for each host in a Logstore named access_log and save the analysis result to a table named T2. Then, use a JOIN clause to combine T1 and T2 and query the average request length for each host that is contained in both tables.

Query statement

* | with T1 AS (
  SELECT
    host,
    avg(request_length) length
  FROM    website_log
  GROUP BY
    host
),
T2 AS (
  SELECT
    host,
    avg(request_length) length
  FROM    access_log
  GROUP BY
    host
)
SELECT
  T1.host,
  T1.length,
  T2.length
FROM  T1
  JOIN T2 ON T1.host = T2.host

Query and analysis result