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Finding duplicate values in MySQL
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Do a SELECT with a GROUP BY clause. Let's say name is the column you want to find duplicates in:
SELECT name, COUNT(*) c FROM table GROUP BY name HAVING c > 1;
This will return a result with the name value in the first colum...
How to select lines between two marker patterns which may occur multiple times with awk/sed
Using awk or sed how can I select lines which are occurring between two different marker patterns? There may be multiple sections marked with these patterns.
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SQL query for finding records where count > 1
...ers that have more than one payment per day with the same account number
SELECT
user_id ,
COUNT(*) count
FROM
PAYMENT
GROUP BY
account,
user_id ,
date
Having
COUNT(*) > 1
Update
If you want to only include those that have a distinct ZIP you can get a distinct set first and then perfor...
Add a column to a table, if it does not already exist
...onstruct by using the sys.columns table io sys.objects.
IF NOT EXISTS (
SELECT *
FROM sys.columns
WHERE object_id = OBJECT_ID(N'[dbo].[Person]')
AND name = 'ColumnName'
)
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Distinct in Linq based on only one field of the table
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Try this:
table1.GroupBy(x => x.Text).Select(x => x.FirstOrDefault());
This will group the table by Text and use the first row from each groups resulting in rows where Text is distinct.
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SQLite: How do I save the result of a query as a CSV file?
... file output.
sqlite> .mode csv
sqlite> .output test.csv
sqlite> select * from tbl1;
sqlite> .output stdout
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CASCADE DELETE just once
...you want to cascade.
DELETE FROM some_child_table WHERE some_fk_field IN (SELECT some_id FROM some_Table);
DELETE FROM some_table;
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follow
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PostgreSQL create table if not exists
..._mytable()
RETURNS void
LANGUAGE plpgsql AS
$func$
BEGIN
IF EXISTS (SELECT FROM pg_catalog.pg_tables
WHERE schemaname = 'myschema'
AND tablename = 'mytable') THEN
RAISE NOTICE 'Table myschema.mytable already exists.';
ELSE
CREATE TABLE myschema...
How to select a node using XPath if sibling node has a specific value?
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Q: How to select a node using XPath if sibling node has a specific value?
Because there are only "XPath Axes" for following-siblings and preceding-siblings, you can use one of them if the position is fixed.
But better:
Look for cc w...
How can I suppress column header output for a single SQL statement?
...in batch (using the mysql command-line binary). I want one of my several SELECT statements to not print the column headers, just the selected records. Is this possible?
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