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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...
MySQL > Table doesn't exist. But it does (or it should)
I changed the datadir of a MySQL installation and all the bases moved correctly except for one.
I can connect and USE the database. SHOW TABLES also returns me all the tables correctly, and the files of each table exists on the MySQL data directory.
...
gem install: Failed to build gem native extension (can't find header files)
I am using Fedora 14 and I have MySQL and MySQL server 5.1.42 installed and running.
Now I tried to do this as root user:
1...
Get the week start date and week end date from week number
...ple:
WITH TestData(SomeDate) AS (
SELECT CAST('20001225' AS DATETIME) UNION ALL
SELECT CAST('20001226' AS DATETIME) UNION ALL
SELECT CAST('20001227' AS DATETIME) UNION ALL
SELECT CAST('20001228' AS DATETIME) UNION ALL
SELECT CAST('20001229' AS DATETIME) UNION ALL
SELECT CAST...
How to select only date from a DATETIME field in MySQL?
I have a table in the MySQL database that is set up with DATETIME . I need to SELECT in this table only by DATE and excluding the time.
...
Python mysqldb: Library not loaded: libmysqlclient.18.dylib
I just compiled and installed mysqldb for python 2.7 on my mac os 10.6. I created a simple test file that imports
15 Answe...
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 ...
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...
MQTT物联网协议完全实践指南 · App Inventor 2 中文网
...概念到高级应用的各个方面。通过实际项目案例，展示了如何使用App Inventor构建可靠的物联网应用，包括：
完整的MQTT连接管理：自动重连、错误处理、状态监控
智能数据处理：实时数据分析、自动控制、告警系统
高级功...
Sql Server string to date conversion
...tedDate,
100 as FormatValue,
'mon dd yyyy hh:miAM (or PM)' as OutputFormat
union all
select @d,convert(varchar,@d,101),101,'mm/dd/yy'
union all
select @d,convert(varchar,@d,102),102,'yy.mm.dd'
union all
select @d,convert(varchar,@d,103),103,'dd/mm/yy'
union all
select @d,convert(varchar,@d,104),104,...