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How to change the default charset of a MySQL table?
... in a database, you can use this query and execute the resulted queries : SELECT concat('alter table ', table_name, ' CONVERT TO CHARACTER SET utf8 COLLATE utf8_general_ci;') FROM information_schema.tables WHERE table_schema='<your_database_name>' and table_collation != 'utf8_general_ci' GR...
PostgreSQL Crosstab Query
... - not fit for missing attributes
crosstab(text) with 1 input parameter:
SELECT *
FROM crosstab(
'SELECT section, status, ct
FROM tbl
ORDER BY 1,2' -- needs to be "ORDER BY 1,2" here
) AS ct ("Section" text, "Active" int, "Inactive" int);
Returns:
Section | Active | Inacti...
How to append a char to a std::string?
...ing fails with the error prog.cpp:5:13: error: invalid conversion from ‘char’ to ‘const char*’
13 Answers
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What is the meaning of the prefix N in T-SQL statements and when should I use it?
...1. It is an Nvarchar
This query fails to match Exact Value That Exists.
SELECT TOP 1 * FROM myTable1 WHERE MyCol1 = 'ESKİ'
// 0 result
using prefix N'' fixes it
SELECT TOP 1 * FROM myTable1 WHERE MyCol1 = N'ESKİ'
// 1 result - found!!!!
Why? Because latin1_general doesn't have big...
What is cardinality in MySQL?
...ow cardinality column with only 2 possible values as the index will not be selective enough to be used.
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const char* concatenation
I need to concatenate two const chars like these:
12 Answers
12
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uint8_t vs unsigned char
What is the advantage of using uint8_t over unsigned char in C?
8 Answers
8
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Fetch the row which has the Max value for a column
... multiple rows for the userid where the maximum date is on multiple rows.
select userid,
my_date,
...
from
(
select userid,
my_date,
...
max(my_date) over (partition by userid) max_my_date
from users
)
where my_date = max_my_date
"Analytic functions rock"
Edi...
Storing SHA1 hash values in MySQL
...
I would use VARCHAR for variable length data, but not with fixed length data. Because a SHA-1 value is always 160 bit long, the VARCHAR would just waste an additional byte for the length of the fixed-length field.
And I also wouldn’t sto...
Creating Unicode character from its number
I want to display a Unicode character in Java. If I do this, it works just fine:
13 Answers
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