Is it possible to execute a LIKE statement against a table column that contains DECIMAL types? Or else, what would be the best way to select matching rows given a number in a decimal (or integer) field?
E.g.:
Name Age
... ...
John 25
Mary 76
Jim 45
Erica 34
Anna 56
Bob 55
Executing something like SELECT * FROM table WHERE age LIKE 5 would return:
Name Age
John 25
Jim 45
Anna 56
Bob 55
It is not clear from your question what exactly you are trying to achieve, but based on the example query, the filtering you need to do should be achievable using normal arithmetic operators.
SELECT * FROM table WHERE MOD(age, 10) = 5 -- All records where the age ends in 5
Or:
SELECT * FROM table WHERE MOD(age, 5) = 0 -- All records where age is divisible by 5
Now that you clarified that though you are using a DECIMAL field you are not actually using it as a numeric value (as if you would, the requirement wouldn't exist), the answers given by others are reasonable - convert the field to a text value and use LIKE on it.
Alternatively, change the type of the field to something that is more suitable to the way you are using it.
You can convert your decimal field to varchar and then apply like.
If you create a query
select name from table where age like '%5%'
you could achieve this (at least in mysql and db2)
But if you prefer to match a number you should use something like:
select name from table where age > minimum and age < maximum
Or try to compare against a modulo if you are really interested in querying on the last number.
Related
I have ID | Name | Salary with types as Integer | String | Integer respectively.
I need to query the avg of all the rows of the Salary column, and then query the avg of all the rows of the Salary column again, but if any of those rows contain 0, remove 0 from those numbers, and calculate the avg.
So like if Salary returns 1420, 2006, 500, the next query should return 142, 26, 5. Then I calculate the avg of the subsequent numbers not containing 0.
I tried googling my specific problem but am not finding anything close to a solution. I'm not looking for an answer too much more than a shove in the right direction.
My Thoughts
Maybe I need to convert the integer data type to a varchar or string then remove the '0' digit from there, then convert back?
Maybe I need to create a temporary table from the first tables results, and insert them, just without 0?
Any ideas? Hope I was clear. Thanks!
Sample table data:
ID | Name | Salary
---+----------+-------
1 | Kathleen | 1420
2 | Bobby | 690
3 | Cat | 500
Now I need to query the above table but with the 0's removed from the salary rows
ID | Name | Salary
---+----------+-------
1 | Kathleen | 142
2 | Bobby | 69
3 | Cat | 5
You want to remove all 0s from your numbers, then take a numeric average of the result. As you are foreseeing, this requires mixing string and numeric operations.
The actual syntax will vary across databases. In MySQL, SQL Server and Oracle, you should be able to do:
select avg(replace(salary, '0', '') + 0) as myavg
from mytable
This involves two steps of implicit conversion: replace() forces string context, and + 0 turns the result back to a number. In SQL Server, you will get an integer result - if you want a decimal average instead, you might need to add a decimal value instead - so + 0.0 instead of + 0.
In Postgres, where implicit conversion is not happening as easily, you would use explicit casts:
select avg(replace(salary::text, '0', '')::int) as myavg
from mytable
This returns a decimal value.
Do you just want conditional aggregation?
select avg(salary), avg(case when salary <> 0 then salary end)
from t;
or do you want division?
select id, name, floor(salary / 10)
from t;
This produces the results you specify but it has nothing to do with "average"s.
In SQLite how do I get the row number of a specific result?
Consider my data is the following
Username UserLevel
James 23
Tim 24
John 22
What I'd like to return is the position in the statement where said person is. IE
Select * from users where Username='John' (+ SOME LOGIC);
Returns
3
Thanks!
you can use ROW_NUMBER(). ROW_NUMBER is a temporary value calculated when the query is run
I have a table of rates and terms from which I need to use the term to select the appropriate rate adjustment. The issue is, each term is its own column as so:
term 12mon 24mon 36mon
----- ----- ----- -----
12 2 4 6
24 2 4 6
I need, for each term, to return the correct adjuster.
Thus for 12 months I would need a "2" and for 24 it would be "4" and so on. While vastly oversimplified it captures the essence - I need to select a column name in a table based upon the value of another column in the same table.
I'm not able to change the source table.
Thanks in advance...
case is your friend
case term
when 12 then [12mon]
when 24 then [24mon]
when 36 then [36 mon]
end as rate
if value of term can be between 12 and 24, etc. then write it this way (I'm not sure what your logic needs to be, but you get the idea)
case
when term < 12 then 0
when term < 24 then [12mon]
when term < 36 then [24mon]
when term < 48 then [36mon]
else [48mon]
end as rate
What flavor of SQL is that ?
In most of them you can use CASE WHEN (predicate) THEN x statements which you can use to get different columns and then alias it.
In SQL, say I have a table of the following layout:
id name age
1 george 12
2 tom 14
3 charles 19
4 henry 21
5 fiona 12
6 kate 14
...
If I discover that I've made a terrible inputting mistake, and that everybody is actually twice their age, is there a way to multiply the age column by 2 in one sweep instead of needing to painstakingly go through the whole column and edit each age individually (pretend I have 500 entries so manual work is out of the question).
Is there a SQL solution?
It's really easy:
UPDATE table SET age=age*2
Yes, run an update:
update theTable set age = age * 2
Depending on the settings in the database, you might not be allowed to run an update without a where (to protect against mistakes), then you would add a dummy comparison:
update theTable set age = age * 2 where 1 = 1
I found a very interesting/strange thing about MAX() function in SQL.
I have column ID with varchar2(20) data type, having following entries:-
ID
1
2
3
4
5
6
9
99
909
As per my understanding if i use "select max(ID) from table;" I should get 909 as the result but i get 99. Can somebody explain why this is happening?
You have misunderstood - since the column is a varchar, not numeric, it is sorted by string values; 909 comes before 99, so 99 is the maximum.
To see the maximum numeric value of your column, try:
select max(to_number(ID)) from my_table
Since the column you are using MAX on is of type VARCHAR, it is going to sort the values based on a character-by-character evaluation. It selects 99 because 9 > 0, and it will ignore the rest of the string.
Your column is being represented as characters, not numbers. So think of it as ordering these alphabetically. Alphabetically 909 will come before 99 in ascending order.