[Solved] Recursive CTE Table - Calculating EWMA (EMA) - How to optimize/refactor this code so it doesn\'t get killed by TDWM every time?

## How to optimize this SQL query?

In case you have your own slow SQL query, you can optimize it automatically here.

For the query above, the following recommendations will be helpful as part of the SQL tuning process.
You'll find 3 sections below:

1. Description of the steps you can take to speed up the query.
2. The optimal indexes for this query, which you can copy and create in your database.
3. An automatically re-written query you can copy and execute in your database.
##### The optimization process and recommendations:
1. Avoid Selecting Unnecessary Columns (query line: 37): Avoid selecting all columns with the '*' wildcard, unless you intend to use them all. Selecting redundant columns may result in unnecessary performance degradation.
##### The optimized query:
``````WITH smooth AS (SELECT
CAST(0.741870935 AS NUMERIC (20,
5)) AS alpha), numbered AS (SELECT
ROW_NUMBER() OVER (ORDER
BY
my_table.customer_name,
my_table.closed_date) AS rn,
my_table.customer,
my_table.closed_date,
my_table.metric
FROM
my_table), RECURSIVE EWMA AS (SELECT
numbered.rn,
numbered.customer,
numbered.closed_date,
numbered.metric,
CAST(numbered.metric AS NUMERIC (20,
5)) AS EWMA
FROM
numbered
WHERE
numbered.rn = 1
UNION
ALL SELECT
numbered.rn,
numbered.customer,
numbered.closed_date,
numbered.metric,
smooth.alpha * numbered.metric + (1 - smooth.alpha) * EWMA.EWMA
FROM
EWMA
JOIN
numbered
ON EWMA.rn + 1 = numbered.rn CROSS
JOIN
smooth) SELECT
*
FROM
EWMA
ORDER BY
EWMA.closed_date``````