Best practice when using same query repeatedly - sql

Question

what is the alternative for using same query repeatedly many times. I want to store the query in some place and call it whenever I need it.
I'm computing 4 formulas: MTD sales, MTD previous year sales, MAT sales, MAT previus year sales as separate columns for 5 different products: A,B,C,D,E. along with some static conditions like account details should be provided and direct sales
I'm querying Case statements 4 (for formulas)* 5 (for products) times to define formula with static conditions for all 5 products. i.e. almost 80% of my query is repeated for 4*5 =20 times. Instead of repeating 80% of the query for all 20 times, is there any better way to do it. Kindly note, I don't have to store value of the query as function, instead can I store the repeated portion of the query and call it where ever I need?
Code:
SELECT A1.*,
-- MTD FOR PRODUCTS A,B,C,D
CASE WHEN
ACCOUNT<> 'Not Provided' AND TYPE<> 'DIRECT' and PRODUCT='A'
AND
(EXTRACT (MONTH FROM DATE_MONTH)=EXTRACT(MONTH FROM (SELECT MAX(SHOWN_DATE) FROM TABLE_A))
AND
EXTRACT (YEAR FROM DATE_MONTH)=EXTRACT(YEAR FROM (SELECT MAX(SHOWN_DATE) FROM TABLE_A)))
THEN SALES ELSE 0 END AS MTD_PRODUCT_A,
CASE WHEN
ACCOUNT<> 'Not Provided' AND TYPE<> 'DIRECT' and PRODUCT='B'
AND
(EXTRACT (MONTH FROM DATE_MONTH)=EXTRACT(MONTH FROM (SELECT MAX(SHOWN_DATE) FROM TABLE_A))
AND
EXTRACT (YEAR FROM DATE_MONTH)=EXTRACT(YEAR FROM (SELECT MAX(SHOWN_DATE) FROM TABLE_A)))
THEN SALES ELSE 0 END AS MTD_PRODUCT_B,
CASE WHEN
ACCOUNT<> 'Not Provided' AND TYPE<> 'DIRECT' and PRODUCT='C'
AND
(EXTRACT (MONTH FROM DATE_MONTH)=EXTRACT(MONTH FROM (SELECT MAX(SHOWN_DATE) FROM TABLE_A))
AND
EXTRACT (YEAR FROM DATE_MONTH)=EXTRACT(YEAR FROM (SELECT MAX(SHOWN_DATE) FROM TABLE_A)))
THEN SALES ELSE 0 END AS MTD_PRODUCT_C,
CASE WHEN
ACCOUNT<> 'Not Provided' AND TYPE<> 'DIRECT' and PRODUCT='D'
AND
(EXTRACT (MONTH FROM DATE_MONTH)=EXTRACT(MONTH FROM (SELECT MAX(SHOWN_DATE) FROM TABLE_A))
AND
EXTRACT (YEAR FROM DATE_MONTH)=EXTRACT(YEAR FROM (SELECT MAX(SHOWN_DATE) FROM TABLE_A)))
THEN SALES ELSE 0 END AS MTD_PRODUCT_D,
---MTD LAST YEAR FOR PRODUCTS A,B,C,D
CASE WHEN
ACCOUNT<> 'Not Provided' AND TYPE<> 'DIRECT' and PRODUCT='A'
AND
(EXTRACT (MONTH FROM DATE_MONTH)=EXTRACT(MONTH FROM (SELECT MAX(SHOWN_DATE) FROM TABLE_A))
AND
EXTRACT (YEAR FROM DATE_MONTH)=(SELECT EXTRACT(YEAR FROM MAX(SHOWN_DATE))-1 FROM TABLE_A))
THEN SALES ELSE 0 END AS MTD_PY_PRODUCT_A,
CASE WHEN
ACCOUNT<> 'Not Provided' AND TYPE<> 'DIRECT' and PRODUCT='B'
AND
(EXTRACT (MONTH FROM DATE_MONTH)=EXTRACT(MONTH FROM (SELECT MAX(SHOWN_DATE) FROM TABLE_A))
AND
EXTRACT (YEAR FROM DATE_MONTH)=(SELECT EXTRACT(YEAR FROM MAX(SHOWN_DATE))-1 FROM TABLE_A))
THEN SALES ELSE 0 END AS MTD_PY_PRODUCT_B,
CASE WHEN
ACCOUNT<> 'Not Provided' AND TYPE<> 'DIRECT' and PRODUCT='C'
AND
(EXTRACT (MONTH FROM DATE_MONTH)=EXTRACT(MONTH FROM (SELECT MAX(SHOWN_DATE) FROM TABLE_A))
AND
EXTRACT (YEAR FROM DATE_MONTH)=(SELECT EXTRACT(YEAR FROM MAX(SHOWN_DATE))-1 FROM TABLE_A))
THEN SALES ELSE 0 END AS MTD_PY_PRODUCT_C,
CASE WHEN
ACCOUNT<> 'Not Provided' AND TYPE<> 'DIRECT' and PRODUCT='D'
AND
(EXTRACT (MONTH FROM DATE_MONTH)=EXTRACT(MONTH FROM (SELECT MAX(SHOWN_DATE) FROM TABLE_A))
AND
EXTRACT (YEAR FROM DATE_MONTH)=(SELECT EXTRACT(YEAR FROM MAX(SHOWN_DATE))-1 FROM TABLE_A))
THEN SALES ELSE 0 END AS MTD_PY_PRODUCT_D,
----MAT SALES FOR PRODUCT A,B,C,D
CASE WHEN
ACCOUNT<> 'Not Provided' AND TYPE<> 'DIRECT' and PRODUCT='A'
AND
(Date_Month between add_months(trunc((SELECT MAX(Date_Month) AS MAX_DATE_DIST FROM TABLE_A),'month'),-11)
and
trunc((SELECT MAX(Date_Month) AS MAX_DATE_DIST FROM TABLE_A),'month'))
THEN SALES ELSE 0 END AS MAT_PRODUCT_A,
CASE WHEN
ACCOUNT<> 'Not Provided' AND TYPE<> 'DIRECT' and PRODUCT='B'
AND
(Date_Month between add_months(trunc((SELECT MAX(Date_Month) AS MAX_DATE_DIST FROM TABLE_A),'month'),-11)
and
trunc((SELECT MAX(Date_Month) AS MAX_DATE_DIST FROM TABLE_A),'month'))
THEN SALES ELSE 0 END AS MAT_PRODUCT_B,
CASE WHEN
ACCOUNT<> 'Not Provided' AND TYPE<> 'DIRECT' and PRODUCT='C'
AND
(Date_Month between add_months(trunc((SELECT MAX(Date_Month) AS MAX_DATE_DIST FROM TABLE_A),'month'),-11)
and
trunc((SELECT MAX(Date_Month) AS MAX_DATE_DIST FROM TABLE_A),'month'))
THEN SALES ELSE 0 END AS MAT_PRODUCT_C,
CASE WHEN
ACCOUNT<> 'Not Provided' AND TYPE<> 'DIRECT' and PRODUCT='D'
AND
(Date_Month between add_months(trunc((SELECT MAX(Date_Month) AS MAX_DATE_DIST FROM TABLE_A),'month'),-11)
and
trunc((SELECT MAX(Date_Month) AS MAX_DATE_DIST FROM TABLE_A),'month'))
THEN SALES ELSE 0 END AS MAT_PRODUCT_D,
---MAT LAST YEAR SALES FOR PRODUCTS A,B,C,D
CASE WHEN
ACCOUNT<> 'Not Provided' AND TYPE<> 'DIRECT' and PRODUCT='A'
AND
(Date_Month between add_months(trunc((SELECT MAX(Date_Month) AS MAX_DATE_DIST FROM TABLE_A),'month'),-23)
and
add_months(trunc((SELECT MAX(Date_Month) AS MAX_DATE_DIST FROM TABLE_A),'month'),-12))
THEN SALES ELSE 0 END AS MAT_PRODUCT_A,
CASE WHEN
ACCOUNT<> 'Not Provided' AND TYPE<> 'DIRECT' and PRODUCT='B'
AND
(Date_Month between add_months(trunc((SELECT MAX(Date_Month) AS MAX_DATE_DIST FROM TABLE_A),'month'),-23)
and
add_months(trunc((SELECT MAX(Date_Month) AS MAX_DATE_DIST FROM TABLE_A),'month'),-12))
THEN SALES ELSE 0 END AS MAT_PRODUCT_B,
CASE WHEN
ACCOUNT<> 'Not Provided' AND TYPE<> 'DIRECT' and PRODUCT='C'
AND
(Date_Month between add_months(trunc((SELECT MAX(Date_Month) AS MAX_DATE_DIST FROM TABLE_A),'month'),-23)
and
add_months(trunc((SELECT MAX(Date_Month) AS MAX_DATE_DIST FROM TABLE_A),'month'),-12))
THEN SALES ELSE 0 END AS MAT_PRODUCT_C,
CASE WHEN
ACCOUNT<> 'Not Provided' AND TYPE<> 'DIRECT' and PRODUCT='D'
AND
(Date_Month between add_months(trunc((SELECT MAX(Date_Month) AS MAX_DATE_DIST FROM TABLE_A),'month'),-23)
and
add_months(trunc((SELECT MAX(Date_Month) AS MAX_DATE_DIST FROM TABLE_A),'month'),-12))
THEN SALES ELSE 0 END AS MAT_PRODUCT_D
FROM TABLE_A A1

Answer 1

There are several options.
If the underlying data only needs to be created periodically -- say, once per day or once per week, then you can schedule a job and create a table. This is probably the most common solution across different databases for complicated queries.
If the query itself is not particularly complicated or if you need up-to-date data every time, then use a (regular) view. This is the built-in functionality for encapsulating queries.
Another alternative is a materialized view. These are like tables, in that the data does not need to be (explicitly) recalculated. These are like views, in that the data is kept up-to-date. You can learn more about them in the documentation.

Answer 2

Use an analytical function to find the maximum date value:
SELECT A1.*,
CASE
WHEN ACCOUNT<> 'Not Provided'
AND TYPE<> 'DIRECT'
AND PRODUCT='A'
AND date_month_trunc = max_date_month
THEN SALES
ELSE 0
END AS MTD_PRODUCT_A,
/* B, C, D */
CASE
WHEN ACCOUNT <> 'Not Provided'
AND TYPE<> 'DIRECT'
AND PRODUCT='A'
AND date_month_trunc = max_date_month - INTERVAL '1' YEAR
THEN SALES
ELSE 0
END AS MTD_PY_PRODUCT_A,
/* B, C, D */
CASE
WHEN ACCOUNT<> 'Not Provided'
AND TYPE<> 'DIRECT'
AND PRODUCT='A'
AND date_month BETWEEN ADD_MONTHS( max_date_month - 11 ) AND max_date_month
THEN SALES
ELSE 0
END AS MAT_PRODUCT_A,
/* B, C, D */
CASE
WHEN ACCOUNT<> 'Not Provided'
AND TYPE<> 'DIRECT'
AND PRODUCT='A'
AND date_month BETWEEN ADD_MONTHS( max_date_month, -23 ) AND ADD_MONTHS( max_date_month, -12 )
THEN SALES
ELSE 0
END AS MAT_PRODUCT_A
/* B, C, D */
FROM (
SELECT a.*,
TRUNC( date_month, 'MM' ) AS date_month_trunc,
MAX( TRUNC( date_month, 'MM' ) ) OVER () AS max_date_month
FROM TABLE_A a
) A1
You could make it even shorter by moving common elements of the CASE to the sub-query:
SELECT A1.*,
CASE
WHEN PRODUCT='A'
AND date_month_trunc = max_date_month
THEN not_provided_direct_sales
ELSE 0
END AS MTD_PRODUCT_A,
/* B, C, D */
CASE
WHEN PRODUCT='A'
AND date_month_trunc = max_date_month - INTERVAL '1' YEAR
THEN not_provided_direct_sales
ELSE 0
END AS MTD_PY_PRODUCT_A,
/* B, C, D */
CASE
WHEN PRODUCT='A'
AND date_month BETWEEN ADD_MONTHS( max_date_month - 11 ) AND max_date_month
THEN not_provided_direct_sales
ELSE 0
END AS MAT_PRODUCT_A,
/* B, C, D */
CASE
WHEN PRODUCT='A'
AND date_month BETWEEN ADD_MONTHS( max_date_month, -23 ) AND ADD_MONTHS( max_date_month, -12 )
THEN not_provided_direct_sales
ELSE 0
END AS MAT_PRODUCT_A
/* B, C, D */
FROM (
SELECT a.*,
CASE
WHEN ACCOUNT<> 'Not Provided'
AND TYPE<> 'DIRECT'
THEN SALES
ELSE 0
END AS not_provided_direct_sales,
TRUNC( date_month, 'MM' ) AS date_month_trunc,
MAX( TRUNC( date_month, 'MM' ) ) OVER () AS max_date_month
FROM TABLE_A a
) A1