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Can I apply the required attribute to fields in HTML5?
How can I check if a user has selected something from a <select> field in HTML5?
13 Answers
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SQL: How to properly check if a record exists
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It's better to use either of the following:
-- Method 1.
SELECT 1
FROM table_name
WHERE unique_key = value;
-- Method 2.
SELECT COUNT(1)
FROM table_name
WHERE unique_key = value;
The first alternative should give you no result or one result, the second count should be zero or on...
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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How to make an Android Spinner with initial text “Select One”?
I want to use a Spinner that initially (when the user has not made a selection yet) displays the text "Select One". When the user clicks the spinner, the list of items is displayed and the user selects one of the options. After the user has made a selection, the selected item is displayed in the Spi...
MySQL select where column is not empty
In MySQL, can I select columns only where something exists?
13 Answers
13
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Selecting data from two different servers in SQL Server
How can I select data in the same query from two different databases that are on two different servers in SQL Server?
15 An...
SQL Server loop - how do I loop through a set of records
how do I loop through a set of records from a select?
8 Answers
8
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SELECT INTO using Oracle
I'm trying to do a SELECT INTO using Oracle. My query is:
3 Answers
3
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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;
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Find rows that have the same value on a column in MySQL
...sses and how many times they're used, with the most used addresses first.
SELECT email,
count(*) AS c
FROM TABLE
GROUP BY email
HAVING c > 1
ORDER BY c DESC
If you want the full rows:
select * from table where email in (
select email from table
group by email having count(*) &g...