I have been using NVL in my WHERE clause and it worked well till now.
But in such case where the column has NULL value and parameter was also NULL, it didnt return any query.
select * from Table
where
f_date BETWEEN NVL(:F_DATE_FROM,F_DATE) AND NVL(:F_DATE_TO,F_DATE)
AND op_code = NVL(:CODE, OP_CODE)
AND T_CBC = NVL(:TO_CBC,T_CBC)
order by fiscal_date desc
I updated the query as below, and it returns me all the records as expected. However it takes way too long to execute the query. The original query took 1.5min and the new query takes 7min. Is there any way to fine tune the below query please?
select * from Table
where
f_date BETWEEN NVL(:F_DATE_FROM,F_DATE) AND NVL(:F_DATE_TO,F_DATE)
AND (OP_CODE = :CODE or :CODE is null)
AND (T_CBC = :TO_CBC or :TO_CBC is null)
order by fiscal_date desc
Sure:
WHERE
(f_date >= :F_DATE_FROM OR :F_DATE_FROM IS NULL) AND
(f_date <= :F_DATE_TO OR :F_DATE_TO IS NULL) AND
...
though I'm not sure how much of a performance improvement it'll realize. If your query is about performance specifically, ask a question that includes a query plan
Related
I re-wrote a query to reduce the time it takes to pick the records. But still I see that there is a small tuning that needs to be done in the decode line as the cost is high. Can someone please let me know if the same query can be re-written without the decode functionality? The purpose of removing the decode function would be to use the index in v_id column.
What I have tried so far.
Tried creating a function index (Knowing that bind variables cannot be used) and it failed.
Have tried using the OR condition but it would not pick the index. So any suggestion would be of a great help.
Query is given below.:
SELECT SUM(NVL(dd.amt,0))
FROM db,dd
WHERE db.id = dd.dsba_id
AND dd.nd_id = xxxxxxx
AND dd.a_id = 'xxxxx-xx'
AND DECODE (db.v_id , xxxxxxxxx, 'COMPLETE' , db.code ) = 'COMPLETE'
AND db.datet BETWEEN TRUNC ( SYSDATE , 'YEAR' ) AND SYSDATE;
I would suggest writing the code as:
SELECT SUM(dd.amt)
FROM db JOIN
dd
ON db.id = dd.dsba_id
WHERE dd.nd_id = xxxxxxx AND
dd.a_id = 'xxxxx-xx' AND
(db.v_id = xxxxxxxxx OR db.code = 'COMPLETE') AND
db.datet >= trunc(sysdate, 'YEAR');
For this query, I would recommend indexes on:
db(nd_id, a_id, id, datet, code)
dd(dsba_id, datet, v_id)
The changes to the above query:
Never use commas in the FROM clause. Always use proper, explicit, standard, readable JOIN syntax. (This does not affect performance, however.)
decode() is rather hard to follow. A simple boolean or is equivalent.
BETWEEN is unnecessary assuming that datet is not in the future.
SUM(NVL()) is not needed, because NULL values are ignored. If you are concerned about NULL result, I would suggest COALESCE(SUM(dd.amt), 0)
How can you use a LET temporary variable inside the Where clause in an OrientDB SQL subQuery.
Here is the context in wich I'm trying to use it.
select *, $t.d from Currency
let $t = (select createdDate.asLong() as d from 13:1)
where createdDate.asLong() >= $t.d and #rid <> #13:1
order by createdDate ASC
The validation in the where statement for the dates does not work. The subQuery actually works on its own. The Query works as well when replacing $t.d with the result from the subQuery.
The $t.d is an array so you are comparing something like createdDate.asLong() >= [1234599]
You have to do this: createdDate.asLong() >= $t[0].d
I have a bunch of report parameters and as a result my criteria checking first checks if parameter value is null and if not compares it with a column value .
(#dateStart IS NULL OR #dateStart <= BELGE.AccDate)
AND (#dateEnd IS NULL OR #dateEnd >= BELGE.AccDate)
AND (#CompanyId IS NULL OR #CompanyId = hrktlr.CompanyId)
AND ((#onKayitlarDahil = 1 and hrktlr.StatusCode in ('M', 'O'))
OR (#onKayitlarDahil = 0 AND hrktlr.StatusCode = 'M'))
AND (#BizPartnerId IS NULL or CK.BizPartnerId = #BizPartnerId)
AND (#BizPartnerKodStart is null or #BizPartnerKodStart = '' or #BizPartnerKodStart <= CK.BizPartnerKod)
AND (#BizPartnerKodEnd is null or #BizPartnerKodEnd = '' or #BizPartnerKodEnd >= CK.BizPartnerKod)
AND (#BizPartnerType is null or #BizPartnerType=CK.BizPartnerType)
this is great for a maintainable sql query, but the problem is that Sql Query Optimizer prepares itself for the worst case I guess, and index usage is bad. For example when I pass in BizPartnerId and thus avoid BizPartnerId is null check, query runs a 100 times faster.
So if I keep going with this approach are there any pointers that you can recommend for Query Planner to help increase query performance.
Any viable alternatives to optional parameter checking?
To stop sql server form saving a sub optimal query plan you can use the option WITH RECOMPILE. The query plan will be recalculated each time you run the query.
Here is the where clause of the SQL. when I'm removing this part, it's taking 3 mins to execute, with this one it's taking more than 15 mins
there are almost 9000 records in DB
WHERE username = 'xyz' AND
(
( acceptedfordeliverytime BETWEEN '2012-9-1' AND '2013-1-29' )
OR
(
YEAR(acceptedfordeliverytime) = YEAR('2013-1-29')
AND
MONTH(acceptedfordeliverytime) = MONTH('2013-1-29')
AND
DAY(acceptedfordeliverytime) = DAY('2013-1-29')
)
OR
(
YEAR(acceptedfordeliverytime) = YEAR('2012-9-1')
AND
MONTH(acceptedfordeliverytime) = MONTH('2012-9-1')
AND
DAY(acceptedfordeliverytime) = DAY('2012-9-1')
)
)
Why don't you just use:
WHERE username = 'xyz' AND
(acceptedfordeliverytime >= '2012-09-01' AND
acceptedfordeliverytime < '2013-01-30'
)
This will also allow an index on (username, acceptedfordeliverytime) to be used when executing the query.
I think this will give you the same results.
and also make an index for column acceptedfordeliverytime to speed up searching.
WHERE username = 'xyz' AND acceptedfordeliverytime BETWEEN '2012-9-1' AND '2013-1-29'
Isn't BETWEEN inclusive? This would mean that you don't need all the extra clauses (that check for the first and last date in a VERY elaborate way). I believe your query would return the same result if you just did:
WHERE username = 'xyz' AND
(
acceptedfordeliverytime BETWEEN '2012-9-1' AND '2013-1-29'
)
Your both OR part is unnecessary.
when you use
acceptedfordeliverytime Between '2012-9-1' AND '2013-1-29'
It used both date included so OR part is not needed. if you have date and time in your database then you can convert it into date like this
CAST(acceptedfordeliverytime as date) Between '2012-9-1' AND '2013-1-29'
In MySQL, is there a way to set the "total" fields to zero if they are NULL?
Here is what I have:
SELECT uo.order_id, uo.order_total, uo.order_status,
(SELECT SUM(uop.price * uop.qty)
FROM uc_order_products uop
WHERE uo.order_id = uop.order_id
) AS products_subtotal,
(SELECT SUM(upr.amount)
FROM uc_payment_receipts upr
WHERE uo.order_id = upr.order_id
) AS payment_received,
(SELECT SUM(uoli.amount)
FROM uc_order_line_items uoli
WHERE uo.order_id = uoli.order_id
) AS line_item_subtotal
FROM uc_orders uo
WHERE uo.order_status NOT IN ("future", "canceled")
AND uo.uid = 4172;
The data comes out fine, except the NULL fields should be 0.
How can I return 0 for NULL in MySQL?
Use IFNULL:
IFNULL(expr1, 0)
From the documentation:
If expr1 is not NULL, IFNULL() returns expr1; otherwise it returns expr2. IFNULL() returns a numeric or string value, depending on the context in which it is used.
You can use coalesce(column_name,0) instead of just column_name. The coalesce function returns the first non-NULL value in the list.
I should mention that per-row functions like this are usually problematic for scalability. If you think your database may get to be a decent size, it's often better to use extra columns and triggers to move the cost from the select to the insert/update.
This amortises the cost assuming your database is read more often than written (and most of them are).
None of the above answers were complete for me.
If your field is named field, so the selector should be the following one:
IFNULL(`field`,0) AS field
For example in a SELECT query:
SELECT IFNULL(`field`,0) AS field, `otherfield` FROM `mytable`
Hope this can help someone to not waste time.
You can try something like this
IFNULL(NULLIF(X, '' ), 0)
Attribute X is assumed to be empty if it is an empty String, so after that you can declare as a zero instead of last value. In another case, it would remain its original value.
Anyway, just to give another way to do that.
Yes IFNULL function will be working to achieve your desired result.
SELECT uo.order_id, uo.order_total, uo.order_status,
(SELECT IFNULL(SUM(uop.price * uop.qty),0)
FROM uc_order_products uop
WHERE uo.order_id = uop.order_id
) AS products_subtotal,
(SELECT IFNULL(SUM(upr.amount),0)
FROM uc_payment_receipts upr
WHERE uo.order_id = upr.order_id
) AS payment_received,
(SELECT IFNULL(SUM(uoli.amount),0)
FROM uc_order_line_items uoli
WHERE uo.order_id = uoli.order_id
) AS line_item_subtotal
FROM uc_orders uo
WHERE uo.order_status NOT IN ("future", "canceled")
AND uo.uid = 4172;