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MySQL ON vs USING?
...fferences are noteworthy:
ON is the more general of the two. One can join tables ON a column, a set of columns and even a condition. For example:
SELECT * FROM world.City JOIN world.Country ON (City.CountryCode = Country.Code) WHERE ...
USING is useful when both tables share a column of the exac...
Why does overflow:hidden not work in a ?
I've got a table cell that I would always like to be a particular width. However, it doesn't work with large strings of unspaced text. Here's a test case:
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Oracle SQL: Update a table with data from another table
Table 1:
7 Answers
7
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SQLiteDatabase.query method
...
tableColumns
null for all columns as in SELECT * FROM ...
new String[] { "column1", "column2", ... } for specific columns as in SELECT column1, column2 FROM ... - you can also put complex expressions here:
new String[] { "(...
MySQL - why not index every field?
...n called), so it could potentially slow read operations as well (for large tables).
Check this out
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Fastest way to flatten / un-flatten nested JSON objects
...object:
var flatten = (function (isArray, wrapped) {
return function (table) {
return reduce("", {}, table);
};
function reduce(path, accumulator, table) {
if (isArray(table)) {
var length = table.length;
if (length) {
var index ...
Why not use tables for layout in HTML? [closed]
It seems to be the general opinion that tables should not be used for layout in HTML.
66 Answers
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Postgres and Indexes on Foreign Keys and Primary Keys
...ys? How can I tell? Is there a command that will return all indexes on a table?
7 Answers
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How to list records with date from the last 10 days?
...hy don't you just try it?
The standard ANSI SQL format would be:
SELECT Table.date
FROM Table
WHERE date > current_date - interval '10' day;
I prefer that format as it makes things easier to read (but it is the same as current_date - 10).
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Computed / calculated / virtual / derived columns in PostgreSQL
...enerated columns are introduced with Postgres 12. Trivial example:
CREATE TABLE tbl (
int1 int
, int2 int
, product bigint GENERATED ALWAYS AS (int1 * int2) STORED
);
db<>fiddle here
VIRTUAL generated columns may come with one of the next iterations. (Not in Postgres 13, yet) .
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