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How to do an INNER JOIN on multiple columns
...nds flights either by the city name or the airport code, but the flights table only contains the airport codes so if I want to search by city I have to join on the airports table.
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What's the difference between using INDEX vs KEY in MySQL?
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There's no difference. They are synonyms.
From the CREATE TABLE manual entry:
KEY is normally a synonym for INDEX. The key attribute PRIMARY KEY can
also be specified as just KEY when given in a column definition. This was
implemented for compatibility with other database sy...
how to mysqldump remote db from local machine
...And change:
mysqldump -P 3310 -h localhost -u mysql_user -p database_name table_name
To:
mysqldump -P 3310 -h 127.0.0.1 -u mysql_user -p database_name table_name
(do not use localhost, it's one of these 'special meaning' nonsense that probably connects by socket rather then by port)
edit: we...
Using group by on multiple columns
...one group.
To illustrate using an example, let's say we have the following table, to do with who is attending what subject at a university:
Table: Subject_Selection
+---------+----------+----------+
| Subject | Semester | Attendee |
+---------+----------+----------+
| ITB001 | 1 | John ...
Why is the tag deprecated in HTML?
...nvas. It is only deprecated because of the war against marquees, centers, tables, frame which is purely religious, as they all have a place.
– Dmitry
Jun 5 '16 at 18:23
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Update or Insert (multiple rows and columns) from subquery in PostgreSQL
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For the UPDATE
Use:
UPDATE table1
SET col1 = othertable.col2,
col2 = othertable.col3
FROM othertable
WHERE othertable.col1 = 123;
For the INSERT
Use:
INSERT INTO table1 (col1, col2)
SELECT col1, col2
FROM othertable
You don't ...
Expand div to max width when float:left is set
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The best way is to use a simple 2 cols table instead of wasting time adding tons of CSS not-cross-browser-compatibles tricks
– Marco Demaio
Nov 23 '12 at 10:22
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Nginx缓存解决方案：SRCache - 更多技术 - 清泛网 - 专注C/C++及内核技术
...request_uri_without_args = ngx.re.sub(ngx.var.request_uri, "\\?.*", "")
table.unpack = table.unpack or unpack
for index, rule in ipairs(phoenix["rule"]) do
if type(rule["regex"]) == "string" then
rule["regex"] = {rule["regex"], ""}
end
local regex, options = table.unp...
How do exceptions work (behind the scenes) in c++
...atching_functionv, .-_Z20my_catching_functionv
.section .gcc_except_table,"a",@progbits
.align 4
.LLSDA9:
.byte 0xff
.byte 0x0
.uleb128 .LLSDATT9-.LLSDATTD9
.LLSDATTD9:
.byte 0x1
.uleb128 .LLSDACSE9-.LLSDACSB9
.LLSDACSB9:
.uleb128 .LEHB0-.LFB9
.uleb128 .L...
Rails auto-assigning id that already exists
...to set the sequence for your company.id column to the highest value in the table with a query like this:
SELECT setval('company_id_seq', (SELECT max(id) FROM company));
I am guessing at your sequence name "company_id_seq", table name "company", and column name "id" ... please replace them with th...