大约有 40,000 项符合查询结果（耗时：0.0177秒） [XML]
How can mixed data types (int, float, char, etc) be stored in an array?
...
You can make the array elements a discriminated union, aka tagged union.
struct {
enum { is_int, is_float, is_char } type;
union {
int ival;
float fval;
char cval;
} val;
} my_array[10];
The type member is used to hold the choice of w...
How to delete duplicate rows in SQL Server?
... are deleted (or updated), therefore just change the DELETE FROM CTE... to SELECT * FROM CTE:
WITH CTE AS(
SELECT [col1], [col2], [col3], [col4], [col5], [col6], [col7],
RN = ROW_NUMBER()OVER(PARTITION BY col1 ORDER BY col1)
FROM dbo.Table1
)
DELETE FROM CTE WHERE RN > 1
DEMO (re...
How to remove all MySQL tables from the command-line without DROP database permissions? [duplicate]
...tatements to execute it:
SET FOREIGN_KEY_CHECKS = 0;
SET @tables = NULL;
SELECT GROUP_CONCAT('`', table_schema, '`.`', table_name, '`') INTO @tables
FROM information_schema.tables
WHERE table_schema = 'database_name'; -- specify DB name here.
SET @tables = CONCAT('DROP TABLE ', @tables);
PRE...
Get table names using SELECT statement in MySQL
...
To get the name of all tables use:
SELECT table_name FROM information_schema.tables;
To get the name of the tables from a specific database use:
SELECT table_name FROM information_schema.tables
WHERE table_schema = 'your_database_name';
Now, to answer the...
Schrödingers MySQL table: exists, yet it does not
...or if you have backups, try the following:
Delete all schemas (excluding mysql)
shut down the database
Make sure that all folders in your data directory have been removed properly (again, excluding mysql)
delete ibdata and log files
restart the database. It should recreate the tablespace and logs ...
Composer killed while updating
...out, don't forget to add sudo if you don't work as root.
btw, feel free to select another location/filename/size for the file.
/var is probably not the best place, but I don't know which place would be, and rarely care since tiny servers are mostly used for testing purposes.
...
Why is '+' not understood by Python sets?
...ts don't have an implementation for the + operator.
You can use | for set union and & for set intersection.
Sets do implement - as set difference. You can also use ^ for symmetric set difference (i.e., it will return a new set with only the objects that appear in one set but do not appear in b...
MySQL order by before group by
... table on both the post_author and the max date.
The solution should be:
SELECT p1.*
FROM wp_posts p1
INNER JOIN
(
SELECT max(post_date) MaxPostDate, post_author
FROM wp_posts
WHERE post_status='publish'
AND post_type='post'
GROUP BY post_author
) p2
ON p1.post_author = p...
Disable ONLY_FULL_GROUP_BY
...ove ONLY_FULL_GROUP_BY from mysql console
mysql > SET GLOBAL sql_mode=(SELECT REPLACE(@@sql_mode,'ONLY_FULL_GROUP_BY',''));
you can read more here
Solution 2: Remove ONLY_FULL_GROUP_BY from phpmyadmin
Open phpmyadmin & select localhost
Click on menu Variables & scroll down for sq...
How to check if mysql database exists
...
SELECT SCHEMA_NAME
FROM INFORMATION_SCHEMA.SCHEMATA
WHERE SCHEMA_NAME = 'DBName'
If you just need to know if a db exists so you won't get an error when you try to create it, simply use (From here):
CREATE DATABASE IF NO...