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What is the error “Every derived table must have its own alias” in MySQL?
...er), which can the be used to refer to it in the rest of the outer query.
SELECT ID FROM (
SELECT ID, msisdn FROM (
SELECT * FROM TT2
) AS T
) AS T
In your case, of course, the entire query could be replaced with:
SELECT ID FROM TT2
...
React JSX: selecting “selected” on selected option
In a React component for a <select> menu, I need to set the selected attribute on the option that reflects the application state.
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How do you remove all the options of a select box and then add one option and select it with jQuery?
Using core jQuery, how do you remove all the options of a select box, then add one option and select it?
24 Answers
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MySQL Insert Where query
...INSERT INTO Users(weight, desiredWeight)
VALUES (160,145)
INSERT using a SELECT statement
INSERT INTO Users(weight, desiredWeight)
SELECT weight, desiredWeight
FROM AnotherTable
WHERE id = 1
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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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MySQL Great Circle Distance (Haversine formula)
...ults. To search by kilometers instead of miles, replace 3959 with 6371.
SELECT id, ( 3959 * acos( cos( radians(37) ) * cos( radians( lat ) )
* cos( radians( lng ) - radians(-122) ) + sin( radians(37) ) * sin(radians(lat)) ) ) AS distance
FROM markers
HAVING distance < 25
ORDER BY distance ...
How do I check if a column is empty or null in MySQL?
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This will select all rows where some_col is NULL or '' (empty string)
SELECT * FROM table WHERE some_col IS NULL OR some_col = '';
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Counting null and non-null values in a single query
...le and SQL Server (you might be able to get it to work on another RDBMS):
select sum(case when a is null then 1 else 0 end) count_nulls
, count(a) count_not_nulls
from us;
Or:
select count(*) - count(a), count(a) from us;
...
Return rows in random order [duplicate]
...
SELECT * FROM table
ORDER BY NEWID()
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How to remove an iOS app from the App Store
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What you need to do is this.
Go to “Manage Your Applications” and select the app.
Click “Rights and Pricing” (blue button at the top right.
Below the availability date and price tier section, you should see a grid of checkboxes for the various countries your app is available in. Click t...