Good morning, everyone! I have a pretty simple SELECT/JOIN statement that gets some imported data from a placement test and returns the highest scored attempt a user made, the best score. Users can take this test multiple times, so we just use the best attempt. What if a user makes multiple attempts (say, tak…
Tag: sql
Inner join with Count, multiple tables
I’m having an issue with MS Access to get correct counts on multiple tables. I’m not at all an expert in SQL requests. I have a set of tables which is structured as follow : Table1 : UID, Name, other informations Table2 : UID, FK_UID_Table1, Name, other informations Table3 : UID, FK_UID_Table2, Na…
Is it a performance problem to start add sequential GUIDs in table with non sequential GUIDs
I have tables with primary key uniqueidentifier type and add non sequential ids, now I want just to start adding only sequential ids in this tables. The guid generation is made in the code. Is it possible this to create problems in the indexes of the previous data. Logically I don’t see any problem, but…
system.linq.enumaerable+<Cast… in combobox C#
I have a SQL query that reads string data from a SQL Express DB (Changing over to Azure). Once the data is retrieved, I read it into an array and then display the contents of the array in a combo-box. i am not receiving any error however, in the combo-box, an extra field is displayed and I cannot fgure out
How does spark SQL access databases
Suppose you access a SQL database with spark SQL. With RDD spark partitions the data into many different parts that all together make the data set. My question is how does Spark SQL manages this access from the N nodes to the database. I can see several possibilities: Each nodes of the RDD access to the datab…
SQL interview questions
Table-1 Table-2 And need output is Answer Here’s one option:
‘Tagging’ a record using multiple criteria
I am using Presto. I want to assign a row with multiple ‘tags’ using different criteria that are not mutually exclusive. For example, let’s say there’s a table with 4 columns: | food | color |…
SQL: Delete XML node in an UPDATE statement
I keep getting this error: In search of a solution to this answer I came across this SO article about updating in a SELECT statement: How do I UPDATE from a SELECT in SQL Server? Example… Note: the field CustomProperties is nvarchar(max) which I convert to xml. I also tried a cursor (nasty things), but …
Parsing a variable into a sql statement in Python
I have the following insert statement that let me parse sql query into a python file and then returning a dataframe of that data that is collected from the query params = ‘DRIVER={ODBC Driver 13 …
How to break sequence
i have a table named sequence with a single column val and table looks like val —– 1 2 3 5 8 9 10 i need to identify the range of numbers if there is a break in sequence and output like …