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SQL join: selecting the last records in a one-to-many relationship
... want to get a list of all customers along with their last purchase in one SELECT statement. What is the best practice? Any advice on building indexes?
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Oracle SQL Query for listing all Schemas in a DB
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Using sqlplus
sqlplus / as sysdba
run:
SELECT *
FROM dba_users
Should you only want the usernames do the following:
SELECT username
FROM dba_users
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Vim search and replace selected text
Let's say we have a text, and I enter visual mode and select some text. How do I quickly do a search for the highlighted text and replace it with something else?
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Select last row in MySQL
How can I SELECT the last row in a MySQL table?
10 Answers
10
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Passing an array to a query using a WHERE clause
...y external input is sanitized.
$ids = join("','",$galleries);
$sql = "SELECT * FROM galleries WHERE id IN ('$ids')";
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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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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.
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Removing duplicate rows from table in Oracle
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Use the rowid pseudocolumn.
DELETE FROM your_table
WHERE rowid not in
(SELECT MIN(rowid)
FROM your_table
GROUP BY column1, column2, column3);
Where column1, column2, and column3 make up the identifying key for each record. You might list all your columns.
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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...
What is the purpose of Order By 1 in SQL select statement?
...number stands for the column based on the number of columns defined in the SELECT clause. In the query you provided, it means:
ORDER BY A.PAYMENT_DATE
It's not a recommended practice, because:
It's not obvious/explicit
If the column order changes, the query is still valid so you risk ordering ...