大约有 40,000 项符合查询结果（耗时：0.0295秒） [XML]
ElasticSearch, Sphinx, Lucene, Solr, Xapian. Which fits for which usage? [closed]
... SET NAMES utf8
# query before fetching rows to index
sql_query = SELECT *, id AS pid, CRC32(safetag) as safetag_crc32 FROM hb_posts
sql_attr_uint = pid
# pid (as 'sql_attr_uint') is necessary for sphinx
# this field must be unique
# that is why I like sphinx
# you ...
What's the best way to join on the same table twice?
...tiple times or using subqueries etc.
I would just clean things up a bit:
SELECT t.PhoneNumber1, t.PhoneNumber2,
t1.SomeOtherFieldForPhone1, t2.someOtherFieldForPhone2
FROM Table1 t
JOIN Table2 t1 ON t1.PhoneNumber = t.PhoneNumber1
JOIN Table2 t2 ON t2.PhoneNumber = t.PhoneNumber2
What i did:...
Delimiters in MySQL
...TABLE tablea (
col1 INT,
col2 INT
);
INSERT INTO tablea
SELECT * FROM table1;
CREATE TABLE tableb (
col1 INT,
col2 INT
);
INSERT INTO tableb
SELECT * FROM table2;
/* whole procedure ends with the custom delimiter */
END$$
/* Finally, reset the delimiter to...
Which MySQL data type to use for storing boolean values
...
When I do a select from the standard mysql command line client bit fields shows up completely blank. Because of this I prefer TINYINT(1).
– User
Nov 2 '12 at 0:53
...
How to prevent ifelse() from turning Date objects into numeric objects
...documented option to have base::ifelse() preserve attributes based on user selection of which attributes to preserve. The request is here: https://bugs.r-project.org/bugzilla/show_bug.cgi?id=16609 - It has already been flagged as "WONTFIX" on the grounds that it has always been the way it is now, b...
Drop multiple tables in one shot in mysql
... of tables to be deleted.
Get table using the below
For sql server - SELECT CONCAT(name,',') Table_Name FROM SYS.tables;
For oralce - SELECT CONCAT(TABLE_NAME,',') FROM SYS.ALL_TABLES;
Copy and paste the table names from the result set and paste it after the DROP command.
...
MySQL - why not index every field?
...k about index updates were one update trigger all indexes update this is a select all unordered equivalent in time
from this I conclude that you have in this scenario that if you will loose this time is preferable to lose it in a select nor an update because if you will select a field that is not i...
String concatenation in MySQL
...most DBMSs use of + or || for concatenation. It uses the CONCAT function:
SELECT CONCAT(first_name, " ", last_name) AS Name FROM test.student
As @eggyal pointed out in comments, you can enable string concatenation with the || operator in MySQL by setting the PIPES_AS_CONCAT SQL mode.
...
How to escape single quotes in MySQL
...
Put quite simply:
SELECT 'This is Ashok''s Pen.';
So inside the string, replace each single quote with two of them.
Or:
SELECT 'This is Ashok\'s Pen.'
Escape it =)
...
Types in MySQL: BigInt(20) vs Int(20)
...E TABLE foo ( bar INT(20) ZEROFILL );
INSERT INTO foo (bar) VALUES (1234);
SELECT bar from foo;
+----------------------+
| bar |
+----------------------+
| 00000000000000001234 |
+----------------------+
It's a common source of confusion for MySQL users to see INT(20) and assume ...