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Query 1 | Query 2 |
|---|
| Paste code macro |
|---|
| Select
First_Name
,Last_Name
,Order_Date
,Order_ID
From dbo.Orders
Where Upper(Last_Name) = 'SMITH'
And Order_Date = '2018-12-30' |
|
| Paste code macro |
|---|
| Select
a.First_Name
,a.Last_Name
,a.Order_Date
,a.Order_ID
From (
Select
First_Name
,Last_Name
,Upper(Last_Name) As uc_Last_Name
,Order_Date
,Order_ID
From dbo.Orders
Where Order_Date = '2018-12-30'
)a
Where a.uc_Last_Name = 'SMITH'
|
|
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What is a Union, and Union All? How do they differ? And can you provide an example of their use.
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Which of these two calculations is the most performant in achieving the highlighted row? Explain
| Table Calculation | Level-of-detail Expression |
|---|
| Code Block |
|---|
| Window_Sum(Sum(Sales)) |
|
| Code Block |
|---|
| Sum({Fixed Segment, Category : Sum(Sales)}) |
|
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| Note |
|---|
The version 2020.2 changes to the Tableau data model have superseded this, but this it is still pertinent to for a Tableau developer to understand this |
Consider this ER diagram:
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