Using backticks around field names

2018-12-31 04:54发布

After reading a couple of answers and comments on some SQL questions here, and also hearing that a friend of mine works at a place which has a policy which bans them, I'm wondering if there's anything wrong with using backticks around field names in MySQL.

That is:

SELECT `id`, `name`, `anotherfield` ...
-- vs --
SELECT id, name, anotherfield ...

10条回答
琉璃瓶的回忆
2楼-- · 2018-12-31 05:21

There isn't anything wrong if you keep using MYSQL, except maybe the visual fuziness of the queries. But they do allow the use of reserved keywords or embedded spaces as table and column names. This is a no-no with most database engines and will prevent any migration at a later time.

As for easy reading, many people use caps for SQL keywords, eg.

SELECT some_fied, some_other_field FROM whatever WHERE id IS NULL;
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深知你不懂我心
3楼-- · 2018-12-31 05:22

Using backticks permits you to use alternative characters. In query writing it's not such a problem, but if one assumes you can just use backticks, I would assume it lets you get away with ridiculous stuff like

SELECT `id`, `my name`, `another field` , `field,with,comma` 

Which does of course generate badly named tables.

If you're just being concise I don't see a problem with it, you'll note if you run your query as such

EXPLAIN EXTENDED Select foo,bar,baz 

The generated warning that comes back will have back-ticks and fully qualified table names. So if you're using query generation features and automated re-writing of queries, backticks would make anything parsing your code less confused.

I think however, instead of mandating whether or not you can use backticks, they should have a standard for names. It solves more 'real' problems.

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十年一品温如言
4楼-- · 2018-12-31 05:22

To me it makes a lot of sense to use them at all times when dealing with field names.

  • Firstly, once you get into the habit, it doesn't hurt to just hit the backtick key.
  • Secondly, to me, it makes it easier to see what exactly are the fields in your query, and what are keywords or methods.
  • Lastly, it allows you to use whatever field name you wish when designing your table. Sometimes it makes a lot of sense to name a field "key", "order", or "values"... all of which require backticks when referring to them.
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步步皆殇っ
5楼-- · 2018-12-31 05:27

The only problem with backticks is that they are not ANSI-SQL compliant, e.g. they don't work in SQL Server.

If there is a chance you would have to port your SQL to another database, use double quotes.

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深知你不懂我心
6楼-- · 2018-12-31 05:31

Backticks aren't part of standard ANSI SQL. From the mysql manual:

If the ANSI_QUOTES SQL mode is enabled, it is also allowable to quote identifiers within double quotes

So if you use backticks and then decide to move away from MySQL, you have a problem (although you probably have a lot bigger problems as well)

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墨雨无痕
7楼-- · 2018-12-31 05:36

Simple Thing about backtick `` is use for denote identifier like database_name, table_name etc, and single quote '', double quote "" for string literals, whereas "" use for print value as it is and '' print the value variable hold or in another case print the text his have.

i.e 1.-> use `model`;   
    here `model` is database name not conflict with reserve keyword 'model'
2- $age = 27;
insert into `tbl_people`(`name`,`age`,`address`) values ('Ashoka','$age',"Delhi");

here i used both quote for all type of requirement. If anything not clear let me know..
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