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python list in sql query as parameter
....join(placeholder for unused in l)
query= 'SELECT name FROM students WHERE id IN (%s)' % placeholders
cursor.execute(query, l)
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SQL Server insert if not exists best practice
...k or so? (remember this only takes a few seconds)
– Didier Levy
Mar 14 '11 at 12:35
3
@Didier Lev...
How to set initial value and auto increment in MySQL?
How do I set the initial value for an "id" column in a MySQL table that start from 1001?
10 Answers
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Difference between left join and right join in SQL Server [duplicate]
...ed completely interchangeable. Try however Table2 left join Table1 (or its identical pair, Table1 right join Table2) to see a difference. This query should give you more rows, since Table2 contains a row with an id which is not present in Table1.
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T-SQL stored procedure that accepts multiple Id values
Is there a graceful way to handle passing a list of ids as a parameter to a stored procedure?
6 Answers
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Drop all tables whose names begin with a certain string
...lution may also delete tables created by SQL Server! My solution below avoids this and deletes tables in foreign key dependency order.
– Tony O'Hagan
Jul 19 '15 at 1:15
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PostgreSQL Autoincrement
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Yes, SERIAL is the equivalent function.
CREATE TABLE foo (
id SERIAL,
bar varchar);
INSERT INTO foo (bar) values ('blah');
INSERT INTO foo (bar) values ('blah');
SELECT * FROM foo;
1,blah
2,blah
SERIAL is just a create table time macro around sequences. You can not alter SERIAL...
SQL Joins Vs SQL Subqueries (Performance)?
...vary. The speed will depend a lot on indexes (do you have indexes on both ID columns? That will help a lot...) among other things.
The only REAL way to tell with 100% certainty which is faster is to turn on performance tracking (IO Statistics is especially useful) and run them both. Make sure to...
Inserting data into a temporary table
...
INSERT INTO #TempTable (ID, Date, Name)
SELECT id, date, name
FROM physical_table
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Why does my application spend 24% of its life doing a null check?
...at store a copy of the bytes in RAM. An important one is the L1 cache, typically 16 kilobytes for data and 16 kilobytes for instructions. Small, allowing it to be close to the execution engine. Reading bytes from the L1 cache typically takes 2 or 3 CPU cycles. Next up is the L2 cache, bigger and slo...