I want to get the entry from database using sqlite3 using sqlite_prepare_v2() in c interface and used to get the out put not in the expected order.
want to get the entry in the exact order in which size is given in the where clause but behavior is as below:
sqlite> select id,size from audio where size in (9,16,8);
3|9
4|8
5|16
sqlite>
sqlite> select id,size from audio where size in (8,9,16);
3|9
4|8
5|16
sqlite>
sqlite> select id,size from audio where size in (16,8,9);
3|9
4|8
5|16
For the first query, I am expecting the ouput to be in other order of size inside the where clause, but is seems sqlite is by default always giving the output in the order of the id. here id is the primary key field. Is sqlite using any default indexing on primary key field making this to happen? or is there a way to get the output from the sqlite as it is given in the where clause? Please let me know. Thanks.
The order of the in() clause is irrelevant to the order of the select results.
In order to get the select results in the desired order, you must either add an explicit order by clause that fits your need, such as order by size in the second case, or you must issue 3 separate select statements in the desired order.
Related
I'm trying to partition an existing table but I need to use Where or like clause.
The problem is I can't partition it cause every query I wrote, I get an error.
My last code is:
select *
into agg partition by range (subscriberid)
(subscriberid values LIKE '%42' on seg1)
from ncs_sub_unsub;
I've tried a lot of sources to get the answer how I can use a WHERE clause and the partition
Note: the Where and like clause is an initial part of the partitioning
My table : ncs_sub_unsub
The uniqure identifier is : subscriberid
I have the following simplified query which should filter the decrypted column values
SELECT ResourceId, ClientId, UserName
FROM dbo.Resources
WHERE DecrpytByKey(UserName) LIKE '%PETER%';
It doesn't work and returns me 0 results
If I use
SELECT K.ResourceId, K.ClientId, K.DUserName
FROM (
SELECT ResourceId, ClientId, UserName, DecrpytByKey(UserName) AS DUserName
FROM dbo.Resources
) AS K
WHERE K.DUserName LIKE '%PETER%'
This works correctly and gives me the desired results.
I want to go with something similar to option #1, since I want it to be efficient and filter the results before the join.
Is there a way to filter based on the decrypted value in the same select statement?
I'm not sure why it doesn't work, but your queries are doing exactly the same thing. Both of them are doing full scan on table so performance will be same.
Unfortunately, %% in this case are making performance fix impossible.
I'm trying to insert records into a table in a certain (and simple) order, as the table have an IDENTITY column (e.g. MyTbl (ID INT IDENTITY(1,1), Sale_Date DATE, Product_ID INT, Sales INT).
The query is quite simple (this is just a simplified example):
INSERT INTO MyTbl (Sale_Date, Product_ID, Sales)
SELECT Sale_Date, Product_ID,COUNT(*) as sales
FROM Fact_tbl
GROUP BY Sale_Date,Product_ID
ORDER BY Sale_Date,Product_ID
The expected behavior is that when I select the highest values of the identity ID column, I should see the latest Sale_Date. However, this is not the case. The order of the ID column in the table has nothing to do with the dates. To make things even worse, if I recreate the table and run the same INSERT statement again and again and again, I'm getting different order of insertion each time for the same data.
I'm getting this behavior even if I encase the query and put the ORDER BY in or out of the casing.
I never saw this behavior in any other SQL platform. Is this the expected behavior in Snowflake?
It's expected. Let me explain the reason:
AUTOINCREMENT and IDENTITY are synonymous. If either is specified for a column, Snowflake utilizes a sequence to generate the values for the column.
https://docs.snowflake.com/en/sql-reference/sql/create-table.html#optional-parameters
There is no guarantee that values from a sequence are contiguous (gap-free) or that the sequence values are assigned in a particular order. There is, in fact, no way to assign values from a sequence to rows in a specified order other than to use single-row statements (this still provides no guarantee about gaps).
https://docs.snowflake.com/en/user-guide/querying-sequences.html#sequence-semantics
With Snowflake each INSERT has completely different order than the
same INSERT that ran a couple of minutes ago
No, it should insert the data in expected order because you use "ORDER BY" clause. The issue is, the sequence values are not assigned in a particular order!
It's not easy to verify if the data is sorted when you use "INSERT/SELECT ORDER BY", unless you have access to underlying metadata. For testing, you may define clustering keys on a table that you ingested "sorted" data.
Anyway, if you want to assign IDs matching the order when inserting bulk data, you need to use ROW_NUMBER instead of using an IDENTITY column or any sequence values.
This is not expected behavior in Snowflake. However the way you insert data into your table (with the order by) doesn't affect the order in which the data is stored inside the table. You can leave the order by out in the insert, but you should include it in your select.
Which one of the following queries is faster (LIKE vs CONTAINS)?
SELECT * FROM table WHERE Column LIKE '%test%';
or
SELECT * FROM table WHERE Contains(Column, "test");
The second (assuming you means CONTAINS, and actually put it in a valid query) should be faster, because it can use some form of index (in this case, a full text index). Of course, this form of query is only available if the column is in a full text index. If it isn't, then only the first form is available.
The first query, using LIKE, will be unable to use an index, since it starts with a wildcard, so will always require a full table scan.
The CONTAINS query should be:
SELECT * FROM table WHERE CONTAINS(Column, 'test');
Having run both queries on a SQL Server 2012 instance, I can confirm the first query was fastest in my case.
The query with the LIKE keyword showed a clustered index scan.
The CONTAINS also had a clustered index scan with additional operators for the full text match and a merge join.
I think that CONTAINS took longer and used Merge because you had a dash("-") in your query adventure-works.com.
The dash is a break word so the CONTAINS searched the full-text index for adventure and than it searched for works.com and merged the results.
Also try changing from this:
SELECT * FROM table WHERE Contains(Column, "test") > 0;
To this:
SELECT * FROM table WHERE Contains(Column, '"*test*"') > 0;
The former will find records with values like "this is a test" and "a test-case is the plan".
The latter will also find records with values like "i am testing this" and "this is the greatest".
I didn't understand actually what is going on with "Contains" keyword. I set a full text index on a column. I run some queries on the table.
Like returns 450.518 rows but contains not and like's result is correct
SELECT COL FROM TBL WHERE COL LIKE '%41%' --450.518 rows
SELECT COL FROM TBL WHERE CONTAINS(COL,N'41') ---40 rows
SELECT COL FROM TBL WHERE CONTAINS(COL,N'"*41*"') -- 220.364 rows
I will re-write my doubt to be more easy to understand.
I have one table named SeqNumbers that have only one column of data named PossibleNumbers, that has value from 1 to 10.000.
Then I have another Table named Terminals and one of the columns have the serial numbers of the terminals. What I want is get all the SerialNumbers that not exists in the Terminals table from 1 to 10.000.
I've created the SeqNumbers table only to do this... maybe there's another solution without using it... that's fine to me.
The query I have is:
SELECT PossibleNumbers from SeqNumbers
Where PossibleNumbers NOT IN (SELECT SerialNumbers from Terminals)**
Basically I want to list ALL serial numbers of terminals that doesn't exists in the database.
This Query works fine I think... but the problem is that I don't want all results in a single column.. I want these results displayed in 4 or 5 columns.
For my purpose I can only use the results from the query like that. I cannot use programmatically methods to do that.
Hope this is more clear now... Thanks for all the help...
select x, x+1000 from tablename
Will that do it for you?
If I'm reading this right, you'd probably have to do a self join; something like:
SELECT
LeftValues.ColA,
RightValues.ColA AS ColB
FROM YourTable LeftValues
LEFT JOIN YourTable RightValues ON LeftValues.ColA = RightValues.ColA - 1000
WHERE LeftValues.ColA < 1000
Note: Use the JOIN that makes sense for you (left if you are willing to accept NULLs in ColB, inner if you only want them where both values exist)
You can use a scripting language to parse the MySQL results to format it anyway you like. Are you using PHP to access the database? If so, let me know and I can cook one up for you.
I just saw your new updated question. In this case the order of the columns will be ordered by your SELECT statement and you can also sort too. Here is an example:
SELECT Column1, Column2 FROM my_table ORDER BY Column1, Column2 ASC