Tagged Questions
3
votes
2answers
158 views
How to concatenate a column after x rows?
I have a table with columns
object varchar(255),
frequency tinyint(3) unsigned,
I want to concatenate the objects if the sum of frequencies reach a value. Currently I am doing this in PHP as
.. ...
3
votes
1answer
126 views
A function to check if a column allows NULL
Is there a way to write an insert/update query that checks if a column allows NULLs: If it does set the column to NULL, and '' (empty string) otherwise?
I would be something like:
UPDATE mytable
...
1
vote
1answer
141 views
Is a query with UNIX_TIMESTAMP using indexes in mysql?
If I use
.. WHERE UNIX_TIMESTAMP(`some_timestamp`)>NOW()
in a SELECT, does this query still make use on an index, set on some_timestamp ?
0
votes
1answer
290 views
MySQL - Create a function from another function
I want to create a function same like my old functions.
When I create a table, I can use `AS to other table as follows:
CREATE TABLE dummy2 AS SELECT * FROM dummy1;
Can I do the same thing with ...
0
votes
0answers
58 views
How to perform several operations at DB level
I need to insert 25 000 or 50 000 test rows for make some performance tests in several tables in my DB. I'm using PHP but the script takes to long to run so in shared hosting is a pain! I'm asking if ...
1
vote
2answers
415 views
How do I create a user-defined aggregate function?
I need an aggregate function that MySQL doesn't provide.
I would like it to be in MySQL's flavor of SQL (that is, not in C).
How do I do this? What I'm stuck on is creating an aggregate function -- ...
0
votes
1answer
911 views
MySQL: Why is DATEDIFF and TIMEDIFF/60.0/60.0/24.0 results different?
I have a database with two DATETIME values, and then I generate some new values from them:
tdiff = timediff(d1,d2)+0
day1 = truncate(tdiff/60.0/60.0/24.0,0)
day2 = datediff(d1,d2)+0
All three of ...
0
votes
0answers
302 views
Grouping a comma separated value on common data [closed]
I have a table with col1 id int, col2 as varchar(comma seperated value) and column 3 for assigning group to them.
Table looks like
col1 col2 group
..............................
...
2
votes
3answers
375 views
Finding five-minute interval prior to current time
I want to find the five minute interval just before the current time. So if the current time is 8:43 I want to return 8:35 and 8:40. Here is the query that I have written and it is working as ...
1
vote
0answers
558 views
stored procedure returns ERROR 1305 (42000): FUNCTION does not exist
I have a stored procedure and function as below
CREATE PROCEDURE ProcName()
begin
....
DECLARE curs CURSOR FOR select A.PList, B.nid from persons A inner join articles B on
A.aid=B.id;
....
...
