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How to request a random row in SQL?
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See this post: SQL to Select a random row from a database table. It goes through methods for doing this in MySQL, PostgreSQL, Microsoft SQL Server, IBM DB2 and Oracle (the following is copied from that link):
Select a random row with MySQL:
SELE...
PostgreSQL return result set as JSON array?
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TL;DR
SELECT json_agg(t) FROM t
for a JSON array of objects, and
SELECT
json_build_object(
'a', json_agg(t.a),
'b', json_agg(t.b)
)
FROM t
for a JSON object of arrays.
List of objects
This section de...
MySQL: Insert record if not exists in table
...oDB;
Insert a record:
INSERT INTO table_listnames (name, address, tele)
SELECT * FROM (SELECT 'Rupert', 'Somewhere', '022') AS tmp
WHERE NOT EXISTS (
SELECT name FROM table_listnames WHERE name = 'Rupert'
) LIMIT 1;
Query OK, 1 row affected (0.00 sec)
Records: 1 Duplicates: 0 Warnings: 0
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Is String.Contains() faster than String.IndexOf()?
I have a string buffer of about 2000 characters and need to check the buffer if it contains a specific string.
Will do the check in a ASP.NET 2.0 webapp for every webrequest.
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Is there a goto statement in Java?
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@mwieczorek Not all. "char" is a primitive type and it's unsigned.
– Sergey Krivenkov
Nov 20 '18 at 9:47
add a comment
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Return Boolean Value on SQL Select Statement
How to return a boolean value on SQL Select Statement?
9 Answers
9
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How to use OpenFileDialog to select a folder?
How to use OpenFileDialog to select folders?
8 Answers
8
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How does a hash table work?
...but strong hashing...
size_t random[8][256] = { ...random data... };
const char* p = (const char*)&my_double;
size_t hash = random[0][(unsigned)p[0]] ^
random[1][(unsigned)p[1]] ^
... ^
random[7][(unsigned)p[7]];
Weak but oft-fast hashing...
Many librar...
SQL Server : Columns to Rows
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You can use the UNPIVOT function to convert the columns into rows:
select id, entityId,
indicatorname,
indicatorvalue
from yourtable
unpivot
(
indicatorvalue
for indicatorname in (Indicator1, Indicator2, Indicator3)
) unpiv;
Note, the datatypes of the columns you are unpivoting mus...
SQL Server SELECT into existing table
I am trying to select some fields from one table and insert them into an existing table from a stored procedure. Here is what I am trying:
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