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SQL Server Insert if not exists
I want to insert data into my table, but insert only data that doesn't already exist in my database.
10 Answers
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How to execute a raw update sql with dynamic binding in rails
... MySQL:
st = ActiveRecord::Base.connection.raw_connection.prepare("update table set f1=? where f2=? and f3=?")
st.execute(f1, f2, f3)
st.close
I'm not sure if there are other ramifications to doing this (connections left open, etc). I would trace the Rails code for a normal update to see what it'...
sql “LIKE” equivalent in django query
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Use __contains or __icontains (case-insensitive):
result = table.objects.filter(string__contains='pattern')
The SQL equivalent is
SELECT ... WHERE string LIKE '%pattern%';
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How to find gaps in sequential numbering in mysql?
We have a database with a table whose values were imported from another system. There is an auto-increment column, and there are no duplicate values, but there are missing values. For example, running this query:
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How to pull a random record using Django's ORM?
... solutions with order_by('?')[:N] are extremely slow even for medium-sized tables if you use MySQL (don't know about other databases).
order_by('?')[:N] will be translated to SELECT ... FROM ... WHERE ... ORDER BY RAND() LIMIT N query.
It means that for every row in table the RAND() function will ...
What's the difference between comma separated joins and join on syntax in MySQL? [duplicate]
For example if I were to have a table "Person" with a column "id" that references a column "id" in table "Worker"
5 Answers...
What does multicore assembly language look like?
.... All that's needed is software support for each thread to set up its own tables and messaging queues. The OS uses those to do the actual multi-threaded scheduling.
As far as the actual assembly is concerned, as Nicholas wrote, there's no difference between the assemblies for a single threaded or...
Check if table exists and if it doesn't exist, create it in SQL Server 2008
I am writing a Stored procedure in SQL Server 2008.
I need to check if a table exists in the database. If it doesn't then I need to create it.
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How to convert a string or integer to binary in Ruby?
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Picking up on bta's lookup table idea, you can create the lookup table with a block. Values get generated when they are first accessed and stored for later:
>> lookup_table = Hash.new { |h, i| h[i] = i.to_s(2) }
=> {}
>> lookup_table[1]...
What is the best collation to use for MySQL with PHP? [closed]
...names are involved. Depending on the implementation that uses the database tables, this problem could allow malicious users to create a username matching an administrator account.
This problem exposes itself at the very least in early 5.x versions - I'm not sure if this behaviour as changed later.
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