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How do I (or can I) SELECT DISTINCT on multiple columns?
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SELECT DISTINCT a,b,c FROM t
is roughly equivalent to:
SELECT a,b,c FROM t GROUP BY a,b,c
It's a good idea to get used to the GROUP BY syntax, as it's more powerful.
For your query, I'd do it like this:
UPDATE sale...
Search for all occurrences of a string in a mysql database [duplicate]
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In phpMyAdmin a 'Search' feature is available:
Select particular database not table.
Click 'Search' tab
Enter the search term you want
Select the tables you want to search in
phpMyAdmin screen shot:
The 'Search' feature is also available in MySQL Workbench:
Databa...
MySQL “Group By” and “Order By”
I want to be able to select a bunch of rows from a table of e-mails and group them by the from sender. My query looks like this:
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How to call a PHP function on the click of a button
..."insert" value="insert" />
<input type="submit" class="button" name="select" value="select" />
jQuery:
$(document).ready(function(){
$('.button').click(function(){
var clickBtnValue = $(this).val();
var ajaxurl = 'ajax.php',
data = {'action': clickBtnValu...
How disable Copy, Cut, Select, Select All in UITextView
The UITextView 's Copy, Cut, Select, Select All functionality is shown by default when I press down on the screen. But, in my project the UITextField is only read only. I do not require this functionality. Please tell me how to disable this feature.
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How to delete duplicate rows in SQL Server?
... are deleted (or updated), therefore just change the DELETE FROM CTE... to SELECT * FROM CTE:
WITH CTE AS(
SELECT [col1], [col2], [col3], [col4], [col5], [col6], [col7],
RN = ROW_NUMBER()OVER(PARTITION BY col1 ORDER BY col1)
FROM dbo.Table1
)
DELETE FROM CTE WHERE RN > 1
DEMO (re...
How can I select the first day of a month in SQL?
I just need to select the first day of the month of a given datetime variable.
30 Answers
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MySQL: Set user variable from result of query
...need to move the variable assignment into the query:
SET @user := 123456;
SELECT @group := `group` FROM user WHERE user = @user;
SELECT * FROM user WHERE `group` = @group;
Test case:
CREATE TABLE user (`user` int, `group` int);
INSERT INTO user VALUES (123456, 5);
INSERT INTO user VALUES (111111...
Sql Server equivalent of a COUNTIF aggregate function
...u could use a SUM (not COUNT!) combined with a CASE statement, like this:
SELECT SUM(CASE WHEN myColumn=1 THEN 1 ELSE 0 END)
FROM AD_CurrentView
Note: in my own test NULLs were not an issue, though this can be environment dependent. You could handle nulls such as:
SELECT SUM(CASE WHEN ISNULL(myC...
postgresql - sql - count of `true` values
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SELECT COALESCE(sum(CASE WHEN myCol THEN 1 ELSE 0 END),0) FROM <table name>
or, as you found out for yourself:
SELECT count(CASE WHEN myCol THEN 1 END) FROM <table name>
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