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Efficiently convert rows to columns in sql server
...Code, LastName, AccountNumber
from
(
select value, columnname
from yourtable
) d
pivot
(
max(value)
for columnname in (Firstname, Amount, PostalCode, LastName, AccountNumber)
) piv;
See Demo.
Pivot with unknown number of columnnames
If you have an unknown number of columnnames that you w...
How can I rename a database column in a Ruby on Rails migration?
...
rename_column :table, :old_column, :new_column
You'll probably want to create a separate migration to do this. (Rename FixColumnName as you will.):
script/generate migration FixColumnName
# creates db/migrate/xxxxxxxxxx_fix_column_name....
Newline in markdown table?
I have the following cells in a markdown table:
4 Answers
4
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SQL/mysql - Select distinct/UNIQUE but return all columns?
...
You're looking for a group by:
select *
from table
group by field1
Which can occasionally be written with a distinct on statement:
select distinct on field1 *
from table
On most platforms, however, neither of the above will work because the behavior on the other co...
MySQL Great Circle Distance (Haversine formula)
...
@FosAvance Yes, this query would work if you have markers table with id, lan and lng fields.
– Pavel Chuchuva
Mar 29 '14 at 23:08
|
...
SQL Server - Return value after INSERT
... get a the key-value back after an INSERT-statement.
Example:
I've got a table with the attributes name and id. id is a generated value.
...
Delete duplicate records in SQL Server?
Consider a column named EmployeeName table Employee . The goal is to delete repeated records, based on the EmployeeName field.
...
Can someone explain mappedBy in JPA and Hibernate?
...irline that it is responsible for maintaining the values over in the other table. It is possible to tell an Entity it "owns" a column in a different table and is responsible for updating it. It's not something you usually want to do and can cause problems with the order SQL statements are executed...
“Insert if not exists” statement in SQLite
...te database. I am trying to insert values ( users_id , lessoninfo_id ) in table bookmarks , only if both do not exist before in a row.
...
How to sum a variable by group
...he syntax behind each alternative. For instance, if I have a larger source table and want to subselect just two dimensions plus summed metrics, can I adapt any of these methods? Hard to tell.
– Dodecaphone
Oct 28 '18 at 10:42
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