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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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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
...
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
...
Try this
SELECT ID, Name
FROM Table1
WHERE ID NOT IN (SELECT ID FROM Table2)
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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...
What is the difference between the states selected, checked and activated in Android?
...below added):
... For example, in a list view with single or multiple selection
enabled, the views in the current selection set are activated. (Um,
yeah, we are deeply sorry about the terminology here.) The activated
state is propagated down to children of the view it is set on.
So here...
Fastest way to determine if record exists
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SELECT TOP 1 products.id FROM products WHERE products.id = ?; will outperform all of your suggestions as it will terminate execution after it finds the first record.
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When to use SELECT … FOR UPDATE?
Please help me understand the use-case behind SELECT ... FOR UPDATE .
2 Answers
2
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Insert into … values ( SELECT … FROM … )
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Try:
INSERT INTO table1 ( column1 )
SELECT col1
FROM table2
This is standard ANSI SQL and should work on any DBMS
It definitely works for:
Oracle
MS SQL Server
MySQL
Postgres
SQLite v3
Teradata
DB2
Sybase
Vertica
HSQLDB
H2
AWS RedShift
SA...