Обсуждение: LIMIT 1; The Integer part only
Hello List;
I have two questions:
1) When writing the function (I mean sql function) in the postgresql, I noticed the use for LIMIT 1, but did not
understandwhat does it mean and why we use it?
2) Also in the function (the sql function) in the postgresql, if I need to take the integer part of the number, which
mathfunction can do this for me?
For example, I have 3.900 and I need only the 3 (the integer part), which math function to be used?
Any advise?
Regards
Bilal
bilal ghayyad wrote: > 1) When writing the function (I mean sql function) in the postgresql, I noticed the use for LIMIT 1, but did not understandwhat does it mean and why we use it? > Limit return to 1 record (or other specified number). Note that without ORDER BY, there is no guarantee of which record will show up at the top of the list. See also OFFSET. I.e. to skip the first 30 records and only return the next 10 (records 31-40) in your list: SELECT * from foo order by bar LIMIT 10 OFFSET 30; > 2) Also in the function (the sql function) in the postgresql, if I need to take the integer part of the number, which mathfunction can do this for me? > > For example, I have 3.900 and I need only the 3 (the integer part), which math function to be used? > floor(3.900) Cheers, Steve
On Sep 3, 2009, at 5:49 PM, bilal ghayyad wrote: > 1) When writing the function (I mean sql function) in the > postgresql, I noticed the use for LIMIT 1, but did not understand > what does it mean and why we use it? It restricts the number of rows returned by the SELECT. You can find the documentation here: http://www.postgresql.org/docs/8.4/interactive/sql-select.html#SQL-LIMIT > > 2) Also in the function (the sql function) in the postgresql, if I > need to take the integer part of the number, which math function can > do this for me? floor or trunc, depending on the behavior you want for negative numbers: http://www.postgresql.org/docs/8.4/interactive/functions-math.html -- -- Christophe Pettus xof@thebuild.com