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MySQL - Rows to Columns
...ms that I'll use for the rest of this post. This will be the base table:
select * from history;
+--------+----------+-----------+
| hostid | itemname | itemvalue |
+--------+----------+-----------+
| 1 | A | 10 |
| 1 | B | 3 |
| 2 | A | 9...
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...
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.
...
how do I query sql for a latest record date for each user
...
select t.username, t.date, t.value
from MyTable t
inner join (
select username, max(date) as MaxDate
from MyTable
group by username
) tm on t.username = tm.username and t.date = tm.MaxDate
...
How to deal with SQL column names that look like SQL keywords?
...ange the name because I didn't make it.
Am I allowed to do something like SELECT from FROM TableName or is there a special syntax to avoid the SQL Server being confused?
...
What's faster, SELECT DISTINCT or GROUP BY in MySQL?
...'t, then use DISTINCT.
GROUP BY in MySQL sorts results. You can even do:
SELECT u.profession FROM users u GROUP BY u.profession DESC
and get your professions sorted in DESC order.
DISTINCT creates a temporary table and uses it for storing duplicates. GROUP BY does the same, but sortes the disti...
How do I calculate tables size in Oracle
...BLE_NAME FORMAT A32
COLUMN OBJECT_NAME FORMAT A32
COLUMN OWNER FORMAT A10
SELECT
owner,
table_name,
TRUNC(sum(bytes)/1024/1024) Meg,
ROUND( ratio_to_report( sum(bytes) ) over () * 100) Percent
FROM
(SELECT segment_name table_name, owner, bytes
FROM dba_segments
WHERE segment_type IN...
how to listen to N channels? (dynamic select statement)
...
You can do this using the Select function from the reflect package:
func Select(cases []SelectCase) (chosen int, recv Value, recvOK bool)
Select executes a select operation described by the list of cases. Like
the Go select statement, it bl...
How do I perform an IF…THEN in an SQL SELECT?
How do I perform an IF...THEN in an SQL SELECT statement?
30 Answers
30
...
postgresql: INSERT INTO … (SELECT * …)
...ostgres
CREATE TABLE tblA (id serial, time integer);
INSERT INTO tblA
SELECT id, time
FROM dblink('dbname=dbtest', 'SELECT id, time FROM tblB')
AS t(id integer, time integer)
WHERE time > 1000;
TABLE tblA;
id | time
----+------
1 | 5000
2 | 2000
(2 rows)
PostgreSQL has ...