The question is: are there more reviews with the word "love" or with the word "hate" in them?
Here is the code I am trying to use:
SELECT
(COUNT(SELECT id FROM review WHERE text LIKE '%love%') FROM review) AS NumLove,
(COUNT(SELECT id FROM review WHERE text LIKE '%hate%') FROM review) AS NumHate
FROM
review
Another variation:
SELECT
COUNT(SELECT id FROM review WHERE text LIKE '%love%') AS NumLove,
COUNT(SELECT id FROM review WHERE text LIKE '%hate%') AS NumHate
FROM
review
I am getting an error:
Syntax error near "SELECT"
I have tried to adjust the code a few different times, but I keep getting syntax errors. I can run either of the select statements on their own, and they will execute. I just can't get them to run in a single query.
You need conditional aggregation:
SELECT COUNT(CASE WHEN text LIKE '%love%' THEN 1 END) AS NumLove,
COUNT(CASE WHEN text LIKE '%hate%' THEN 1 END) AS NumHate
FROM review
The important thing to remember is functions are used against columns not result sets. Multiple ways to get there. Aside from the CASE example.
SELECT COUNT(Pro.Love) AS NumLov
FROM
(SELECT id Love FROM review WHERE text LIKE '%love%') as Pro
To write this in one query, you could use a case expression to turn your love and hate evals into 1 and 0 and use Sum instead of count.
SELECT SUM(results.love) AS NumLov
FROM
(
SELECT CASE WHEN text like '%love%' THEN 1 ELSE 0 END AS love
FROM review
) as results
I prefer to use sum instead of count here when using a condition case expression - since you really are adding up (summing) the number of 1s from each case expression
select
Sum(case when text like '%love%' then 1 else 0 end) as NumLove,
Sum(case when text like '%hate%' then 1 else 0 end) as NumHate
from review
Related
I am sure there is a better way to explain this, but essentially here's what I am trying to do
SELECT
CASE WHEN INSTR(stringcolumn,'ex33') = 1 then 1 else 0 end as Tag
FROM TABLE
Below you is what I am trying to accomplish. If the string is found then I want the 1 to show up in all the rows where the txt_id is the same. What is the best way to accomplish this? I have tried with group by but I cannot figure it out. Any guidance would be appreciated.
[
You want a window function:
SELECT t.*,
MAX(CASE WHEN stringcolumn LIKE 'ex33%' THEN 1 ELSE 0 END) OVER (PARTITION BY txt_id) as tag
FROM TABLE;
SQL has the built-in operator LIKE which seems clearer than INSTR().
I want to create a query something like this in django ORM.
SELECT COUNT(CASE WHEN myCondition THEN 1 ELSE NULL end) as numyear
FROM myTable
Following is the djang ORM query i have written
year_case = Case(When(added_on__year = today.year, then=1), output_field=IntegerField())
qs = (ProfaneContent.objects
.annotate(numyear=Count(year_case))
.values('numyear'))
This is the query which is generated by django orm.
SELECT COUNT(CASE WHEN "analyzer_profanecontent"."added_on" BETWEEN 2020-01-01 00:00:00+00:00 AND 2020-12-31 23:59:59.999999+00:00 THEN 1 ELSE NULL END) AS "numyear" FROM "analyzer_profanecontent" GROUP BY "analyzer_profanecontent"."id"
All other things are good, but django places a GROUP BY at the end leading to multiple rows and incorrect answer. I don't want that at all. Right now there is just one column but i will place more such columns.
EDIT BASED ON COMMENTS
I will be using the qs variable to get values of how my classifications have been made in the current year, month, week.
UPDATE
On the basis of comments and answers i am getting here let me clarify. I want to do this at the database end only (obviously using Django ORM and not RAW SQL). Its a simple sql query. Doing anything at Python's end will be inefficient since the data can be too large. Thats why i want the database to get me the sum of records based on the CASE condition.
I will be adding more such columns in the future so something like len() or .count will not work.
I just want to create the above mentioned query using Django ORM (without an automatically appended GROUP BY).
When using aggregates in annotations, django needs to have some kind of grouping, if not it defaults to primary key. So, you need to use .values() before .annotate(). Please see django docs.
But to completely remove group by you can use a static value and django is smart enough to remove it completely, so you get your result using ORM query like this:
year_case = Case(When(added_on__year = today.year, then=1), output_field=IntegerField())
qs = (ProfaneContent.objects
.annotate(dummy_group_by = Value(1))
.values('dummy_group_by')
.annotate(numyear=Count(year_case))
.values('numyear'))
If you need to summarize only to one row then you should to use an .aggregate() method instead of annotate().
result = ProfaneContent.objects.aggregate(
numyear=Count(year_case),
# ... more aggregated expressions are possible here
)
You get a simple dictionary of result columns:
>>> result
{'numyear': 7, ...}
The generated SQL query is without groups, exactly how required:
SELECT
COUNT(CASE WHEN myCondition THEN 1 ELSE NULL end) as numyear
-- and more possible aggregated expressions
FROM myTable
What about a list comprehension:
# get all the objects
profane = ProfaneContent.objects.all()
# Something like this
len([pro for pro in profane if pro.numyear=today.year])
if the num years are equal it will add it to the list, so at the and you can check the len()
to get the count
Hopefully this is helpfull!
This is how I would write it in SQL.
SELECT SUM(CASE WHEN myCondition THEN 1 ELSE 0 END) as numyear
FROM myTable
SELECT
SUM(CASE WHEN "analyzer_profanecontent"."added_on"
BETWEEN 2020-01-01 00:00:00+00:00
AND 2020-12-31 23:59:59.999999+00:00
THEN 1
ELSE 0
END) AS "numyear"
FROM "analyzer_profanecontent"
GROUP BY "analyzer_profanecontent"."id"
If you intend to use other items in the SELECT clause I would recommend using a group by as well which would look like this:
SELECT SUM(CASE WHEN myCondition THEN 1 ELSE 0 END) as numyear
FROM myTable
GROUP BY SUM(CASE WHEN myCondition THEN 1 ELSE 0 END)
I'm attempting to generate a list of vehicles that don't have a price or mileage listed using the below query. When I attempt to run the query, I get an error "ORA-00936: missing expression", but can't seem to find out why. From other posts here, I can see that using IS NULL should be the appropriate term for the WHEN portion, but I am not seeing anything wrong with the query itself. Any help would be appreciated!
Select
SUM(CASE vehicles.mileage WHEN IS NULL THEN 1 ELSE 0 END) NO_MILEAGE,
SUM(CASE vehicles.price WHEN IS NULL THEN 1 ELSE 0 END) NO_PRICE
From
[data]
Simple syntax error:
Select
SUM(CASE WHEN vehicles.mileage IS NULL THEN 1 ELSE 0 END) NO_MILEAGE,
SUM(CASE WHEN vehicles.price IS NULL THEN 1 ELSE 0 END) NO_PRICE
From
[data];
This is assuming a table named vehicles in your FROM clause or a columns with an object or nested table type in [data] named vehicles. Else the qualification vehicles. would not make sense.
Use a "searched" CASE for a decision between two alternatives.
Details about "simple" and "searched" CASE in the Oracle online reference.
You can also use COUNT for your particular case. The online reference again:
If you specify expr, then COUNT returns the number of rows where expr is not null.
If you specify the asterisk (*), then this function returns all rows,
including duplicates and nulls. COUNT never returns null.
So you need the difference:
Select
COUNT(*) - COUNT(vehicles.mileage) AS NO_MILEAGE,
COUNT(*) - COUNT(vehicles.price) AS NO_PRICE
From
[data];
You could also use Oracle's NVL2 function:
Select
SUM(NVL2(vehicles.mileage, 0, 1)) NO_MILEAGE,
SUM(NVL2(vehicles.price, 0, 1)) NO_PRICE
From
[data]
I have query which running fine and its doing two types of work, COUNT and SUM.
Something like
select
id,
Count (contracts) as countcontracts,
count(something1),
count(something1),
count(something1),
sum(cost) as sumCost
from
table
group by
id
My problem is: if there is no contract for a given ID, it will return 0 for COUNT and Null for SUM. I want to see null instead of 0
I was thinking about case when Count (contracts) = 0 then null else Count (contracts) end but I don't want to do it this way because I have more than 12 count positions in query and its prepossessing big amount of records so I think it may slow down query performance.
Is there any other ways to replace 0 with NULL?
Try this:
select NULLIF ( Count(something) , 0)
Here are three methods:
1. (case when count(contracts) > 0 then count(contracts) end) as countcontracts
2. sum(case when contracts is not null then 1 end) as countcontracts
3. nullif(count(contracts), 0)
All three of these require writing more complicated expressions. However, this really isn't that difficult. Just copy the line multiple times, and change the name of the variable on each one. Or, take the current query, put it into a spreadsheet and use spreadsheet functions to make the transformation. Then copy the function down. (Spreadsheets are really good code generators for repeated lines of code.)
I'm building a query with a GROUP BY clause that needs the ability to count records based only on a certain condition (e.g. count only records where a certain column value is equal to 1).
SELECT UID,
COUNT(UID) AS TotalRecords,
SUM(ContractDollars) AS ContractDollars,
(COUNTIF(MyColumn, 1) / COUNT(UID) * 100) -- Get the average of all records that are 1
FROM dbo.AD_CurrentView
GROUP BY UID
HAVING SUM(ContractDollars) >= 500000
The COUNTIF() line obviously fails since there is no native SQL function called COUNTIF, but the idea here is to determine the percentage of all rows that have the value '1' for MyColumn.
Any thoughts on how to properly implement this in a MS SQL 2005 environment?
You could use a SUM (not COUNT!) combined with a CASE statement, like this:
SELECT SUM(CASE WHEN myColumn=1 THEN 1 ELSE 0 END)
FROM AD_CurrentView
Note: in my own test NULLs were not an issue, though this can be environment dependent. You could handle nulls such as:
SELECT SUM(CASE WHEN ISNULL(myColumn,0)=1 THEN 1 ELSE 0 END)
FROM AD_CurrentView
I usually do what Josh recommended, but brainstormed and tested a slightly hokey alternative that I felt like sharing.
You can take advantage of the fact that COUNT(ColumnName) doesn't count NULLs, and use something like this:
SELECT COUNT(NULLIF(0, myColumn))
FROM AD_CurrentView
NULLIF - returns NULL if the two passed in values are the same.
Advantage: Expresses your intent to COUNT rows instead of having the SUM() notation.
Disadvantage: Not as clear how it is working ("magic" is usually bad).
I would use this syntax. It achives the same as Josh and Chris's suggestions, but with the advantage it is ANSI complient and not tied to a particular database vendor.
select count(case when myColumn = 1 then 1 else null end)
from AD_CurrentView
How about
SELECT id, COUNT(IF status=42 THEN 1 ENDIF) AS cnt
FROM table
GROUP BY table
Shorter than CASE :)
Works because COUNT() doesn't count null values, and IF/CASE return null when condition is not met and there is no ELSE.
I think it's better than using SUM().
Adding on to Josh's answer,
SELECT COUNT(CASE WHEN myColumn=1 THEN AD_CurrentView.PrimaryKeyColumn ELSE NULL END)
FROM AD_CurrentView
Worked well for me (in SQL Server 2012) without changing the 'count' to a 'sum' and the same logic is portable to other 'conditional aggregates'. E.g., summing based on a condition:
SELECT SUM(CASE WHEN myColumn=1 THEN AD_CurrentView.NumberColumn ELSE 0 END)
FROM AD_CurrentView
It's 2022 and latest SQL Server still doesn't have COUNTIF (along with regex!). Here's what I use:
-- Count if MyColumn = 42
SELECT SUM(IIF(MyColumn = 42, 1, 0))
FROM MyTable
IIF is a shortcut for CASE WHEN MyColumn = 42 THEN 1 ELSE 0 END.
Not product-specific, but the SQL standard provides
SELECT COUNT() FILTER WHERE <condition-1>,
COUNT() FILTER WHERE <condition-2>, ...
FROM ...
for this purpose. Or something that closely resembles it, I don't know off the top of my hat.
And of course vendors will prefer to stick with their proprietary solutions.
Why not like this?
SELECT count(1)
FROM AD_CurrentView
WHERE myColumn=1
I had to use COUNTIF() in my case as part of my SELECT columns AND to mimic a % of the number of times each item appeared in my results.
So I used this...
SELECT COL1, COL2, ... ETC
(1 / SELECT a.vcount
FROM (SELECT vm2.visit_id, count(*) AS vcount
FROM dbo.visitmanifests AS vm2
WHERE vm2.inactive = 0 AND vm2.visit_id = vm.Visit_ID
GROUP BY vm2.visit_id) AS a)) AS [No of Visits],
COL xyz
FROM etc etc
Of course you will need to format the result according to your display requirements.
SELECT COALESCE(IF(myColumn = 1,COUNT(DISTINCT NumberColumn),NULL),0) column1,
COALESCE(CASE WHEN myColumn = 1 THEN COUNT(DISTINCT NumberColumn) ELSE NULL END,0) AS column2
FROM AD_CurrentView