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MySQL select where column is not empty
In MySQL, can I select columns only where something exists?
13 Answers
13
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What's the difference between INNER JOIN, LEFT JOIN, RIGHT JOIN and FULL JOIN? [duplicate]
...These pictures don't do it for me. Why is the top right picture not simply SELECT * FROM TableA;? Why is the top left picture not simply SELECT * FROM TableB;? Why is the top middle picture not SELECT * FROM A INTERSECT SELECT * FROM B ? etc
– onedaywhen
Sep 9 ...
Display current time in 12 hour format with AM/PM
...nks @RuchiraGayanRanaweei... i just wondering to capture the 24 format and convert it into the AM/PM format...
– gumuruh
Aug 6 '14 at 3:26
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SELECT DISTINCT on one column
...ou're on SQL Server 2005 or greater, you can use a CTE with ROW_NUMBER():
SELECT *
FROM (SELECT ID, SKU, Product,
ROW_NUMBER() OVER (PARTITION BY PRODUCT ORDER BY ID) AS RowNumber
FROM MyTable
WHERE SKU LIKE 'FOO%') AS a
WHERE a.RowNumber = 1
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Coding Practices which enable the compiler/optimizer to make a faster program
...Arithmetic (Edited: applied code format to code fragment, added example)
Convert if statements into boolean assignments. Some processors can conditionally execute instructions without branching:
bool status = true;
status = status && /* first test */;
status = status && /* second...
1052: Column 'id' in field list is ambiguous
...and tbl_section which has both the id field in them. How do I go about selecting the id field, because I always get this error:
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SQL query to find record with ID not in another table
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Try this
SELECT ID, Name
FROM Table1
WHERE ID NOT IN (SELECT ID FROM Table2)
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Append values to a set in Python
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The way I like to do this is to convert both the original set and the values I'd like to add into lists, add them, and then convert them back into a set, like this:
setMenu = {"Eggs", "Bacon"}
print(setMenu)
> {'Bacon', 'Eggs'}
setMenu = set(list(setMen...
Reference alias (calculated in SELECT) in WHERE clause
The calculated value BalanceDue that is set as a variable in the list of selected columns cannot be used in the WHERE clause.
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How to select a single field for all documents in a MongoDB collection?
...nt such as:
db.student.find({}, {roll:1, _id:0})
The above statement will select all documents in the students collection, and the returned document will return only the roll field (and exclude the _id).
If we don't mention _id:0 the fields returned will be roll and _id. The '_id' field is always d...