I have following query
Select id, name, add1 || ' ' ||add2 address,
case
when subId =1 then 'Maths'
else 'Science'
End,
nvl(col1, col2) sampleCol
From Student_tbl
Where department = 'Student'
I want to group by this query by address as default
I tried
Group by add1 ,add2 ,id, name, subId, col1, col2
and
Group by add1 || ' ' ||add2,id, name,
case
when subId =1 then 'Maths'
else 'Science'
End,
nvl(col1, col2)
Both group by returns same result. I am unsure which query is right.
Anybody help me on this?
Always try to implement all the columns (with same format) that you mentioned in the select statement in "Group By" except aggregated columns. In your case I would prefer the second approach.
SELECT id
,NAME
,add1 || ' ' || add2 address
,CASE
WHEN subId = 1
THEN 'Maths'
ELSE 'Science'
END
,nvl(col1, col2) sampleCol
FROM Student_tbl
WHERE department = 'Student'
GROUP BY id
,NAME
,add1 || ' ' || add2
,CASE
WHEN subId = 1
THEN 'Maths'
ELSE 'Science'
END
,nvl(col1, col2)
I can't see any aggregated columns in your Select. If your select does not require aggregation then you can simply get rid off group by. You can implement distinct in case of any duplicate records in your result set.
The two queries will not necessarily give the same result. Which is correct depends on your requirement. Here is an example, using just the new ADDRESS column which you get by aggregating the input columns ADD1 and ADD2.
Suppose in one row you have ADD1 = 123 Main Street, Portland, and ADD2 = Oregon. Then in the output, ADDRESS = 123 Main Street, Portland, Oregon
In another row you have ADD1 = 123 Main Street, and ADD2 = Portland, Oregon. For this row, the resulting ADDRESS is the same.
If you group by ADDRESS the two output rows will land in the same group, but if you group by ADD1, ADD2 they will be in different groups. In this example it is likely you want to group by ADDRESS, but in other, similar-structure cases that wouldn't be what you want or need.
After your last comment I THINK to finally understand what you are expecting from us.
Both queries are correct basically because for both approaches you've listed in your SELECT clause all the fields present in your GROUP BY clause
What you are doing is a bit strange here because the GROUP BY contains the id, I guess this is the unique identifier of each row so you are finally not grouping anything. You'll get as much as rows as your table contains.
The reason why it returns the same reults is purely data based. There might be scenarios where the 2 queries returns different results.
In your case, if it returns the same results, it would mean that col1 is never NULL
Related
I have (and don't own, so I can't change) a table with a layout similar to this.
ID | CATEGORIES
---------------
1 | c1
2 | c2,c3
3 | c3,c2
4 | c3
5 | c4,c8,c5,c100
I need to return the rows that contain a specific category id. I starting by writing the queries with LIKE statements, because the values can be anywhere in the string
SELECT id FROM table WHERE categories LIKE '%c2%';
Would return rows 2 and 3
SELECT id FROM table WHERE categories LIKE '%c3%' and categories LIKE '%c2%'; Would again get me rows 2 and 3, but not row 4
SELECT id FROM table WHERE categories LIKE '%c3%' or categories LIKE '%c2%'; Would again get me rows 2, 3, and 4
I don't like all the LIKE statements. I've found FIND_IN_SET() in the Oracle documentation but it doesn't seem to work in 10g. I get the following error:
ORA-00904: "FIND_IN_SET": invalid identifier
00904. 00000 - "%s: invalid identifier"
when running this query: SELECT id FROM table WHERE FIND_IN_SET('c2', categories); (example from the docs) or this query: SELECT id FROM table WHERE FIND_IN_SET('c2', categories) <> 0; (example from Google)
I would expect it to return rows 2 and 3.
Is there a better way to write these queries instead of using a ton of LIKE statements?
You can, using LIKE. You don't want to match for partial values, so you'll have to include the commas in your search. That also means that you'll have to provide an extra comma to search for values at the beginning or end of your text:
select
*
from
YourTable
where
',' || CommaSeparatedValueColumn || ',' LIKE '%,SearchValue,%'
But this query will be slow, as will all queries using LIKE, especially with a leading wildcard.
And there's always a risk. If there are spaces around the values, or values can contain commas themselves in which case they are surrounded by quotes (like in csv files), this query won't work and you'll have to add even more logic, slowing down your query even more.
A better solution would be to add a child table for these categories. Or rather even a separate table for the catagories, and a table that cross links them to YourTable.
You can write a PIPELINED table function which return a 1 column table. Each row is a value from the comma separated string. Use something like this to pop a string from the list and put it as a row into the table:
PIPE ROW(ltrim(rtrim(substr(l_list, 1, l_idx - 1),' '),' '));
Usage:
SELECT * FROM MyTable
WHERE 'c2' IN TABLE(Util_Pkg.split_string(categories));
See more here: Oracle docs
Yes and No...
"Yes":
Normalize the data (strongly recommended) - i.e. split the categorie column so that you have each categorie in a separate... then you can just query it in a normal faschion...
"No":
As long as you keep this "pseudo-structure" there will be several issues (performance and others) and you will have to do something similar to:
SELECT * FROM MyTable WHERE categories LIKE 'c2,%' OR categories = 'c2' OR categories LIKE '%,c2,%' OR categories LIKE '%,c2'
IF you absolutely must you could define a function which is named FIND_IN_SET like the following:
CREATE OR REPLACE Function FIND_IN_SET
( vSET IN varchar2, vToFind IN VARCHAR2 )
RETURN number
IS
rRESULT number;
BEGIN
rRESULT := -1;
SELECT COUNT(*) INTO rRESULT FROM DUAL WHERE vSET LIKE ( vToFine || ',%' ) OR vSET = vToFind OR vSET LIKE ('%,' || vToFind || ',%') OR vSET LIKE ('%,' || vToFind);
RETURN rRESULT;
END;
You can then use that function like:
SELECT * FROM MyTable WHERE FIND_IN_SET (categories, 'c2' ) > 0;
For the sake of future searchers, don't forget the regular expression way:
with tbl as (
select 1 ID, 'c1' CATEGORIES from dual
union
select 2 ID, 'c2,c3' CATEGORIES from dual
union
select 3 ID, 'c3,c2' CATEGORIES from dual
union
select 4 ID, 'c3' CATEGORIES from dual
union
select 5 ID, 'c4,c8,c5,c100' CATEGORIES from dual
)
select *
from tbl
where regexp_like(CATEGORIES, '(^|\W)c3(\W|$)');
ID CATEGORIES
---------- -------------
2 c2,c3
3 c3,c2
4 c3
This matches on a word boundary, so even if the comma was followed by a space it would still work. If you want to be more strict and match only where a comma separates values, replace the '\W' with a comma. At any rate, read the regular expression as:
match a group of either the beginning of the line or a word boundary, followed by the target search value, followed by a group of either a word boundary or the end of the line.
As long as the comma-delimited list is 512 characters or less, you can also use a regular expression in this instance (Oracle's regular expression functions, e.g., REGEXP_LIKE(), are limited to 512 characters):
SELECT id, categories
FROM mytable
WHERE REGEXP_LIKE('c2', '^(' || REPLACE(categories, ',', '|') || ')$', 'i');
In the above I'm replacing the commas with the regular expression alternation operator |. If your list of delimited values is already |-delimited, so much the better.
I am trying to sum the values from the listagg query i made.
Expected result should be like this
SELECT LEGAL_ENTITY_ID, SUM(0 + 0 + 0 + 1) as Grandtotals
FROM V_VBA_DDCR_MAIN WHERE LEGAL_ENTITY_ID=6012346 AND ROWNUM=1
GROUP BY LEGAL_ENTITY_ID
| LEGAL_ENTITY_ID | GRANDTOTALS
1| 6012346 | 1
My listagg goes like this
SELECT LISTAGG(NVL2(FLDNM,0,1) , '+ ') WITHIN GROUP (ORDER BY FLDNM) FROM LE_MERGE_DDC_MAPPING
the purpose of this query is to count the number of null fields in a row. I created a table containing the list of fields that needs to be checked for null values.
Result :
fld1 + fld2 + fld3 + fld4
=
0 + 0 + 0 + 1
So I wrote my query like this:
SELECT LEGAL_ENTITY_ID, SUM(SELECT LISTAGG(NVL2(FLDNM,0,1) , '+ ') WITHIN GROUP
(ORDER BY FLDNM) FROM LE_MERGE_DDC_MAPPING) as Grandtotals
FROM V_VBA_DDCR_MAIN WHERE LEGAL_ENTITY_ID=6000132
GROUP BY LEGAL_ENTITY_ID
However, I am getting an error ORA-00936: missing expression.
I am not sure if Oracle allows you to do a sum of the listagg function.
Any help is appreciated.
Your SELECT LISTAGG(NVL2(FLDNM,0,1) , '+ ')... query will always get string result '0+ 0+ 0+ ...', unless you have rows in LE_MERGE_DDC_MAPPING which are null. That value is nothing to do with the V_VBA_DDCR_MAIN table. You could generate a string that contains the expressions:
SELECT LISTAGG('NVL2(' || FLDNM || ' ,0,1)' , '+ ') ...
But that would just leave you with a string containing 'NVL2(fld1 ,0,1)+ NVL2(fld2 ,0,1)+ ...'. You can't sum a string, and sum() can't evaluate a string as an expression. You would need to generate a dynamic SQL statement based on that string.
There is a way to do that with XML, which isn't entirely intuitive. You can use the dbms_xmlgen package to create an XML document (as a CLOB) which contains a node with the NVL2 result from your actual target table:
select dbms_xmlgen.getxml('select nvl2(' || fldnm || ',0,1) from v_vba_ddcr_main where legal_entity_id=6012346')
from le_merge_ddc_mapping map;
I won't show the generated XML here. You can then query that to get the individual values out:
select xmlquery('/ROWSET/ROW/*/text()'
passing xmltype(
dbms_xmlgen.getxml('select nvl2(' || fldnm || ',0,1) from v_vba_ddcr_main where Legal_Entity_Id=6012346')
)
returning content)
from le_merge_ddc_mapping;
And you can them sum those:
select sum(to_number(xmlquery('/ROWSET/ROW/*/text()'
passing xmltype(
dbms_xmlgen.getxml('select nvl2(' || fldnm || ',0,1) from v_vba_ddcr_main where legal_entity_id=6012346')
)
returning content))) as grandtotals
from le_merge_ddc_mapping;
You've suggested there is a link between the tables, to determine which fields are included, so you'd need to add that. And you've said there are duplicates, which you'd need to handle - preferably by eliminating them from your view, but with a subquery if necessary. This can be a starting point for you to develop from though.
Why use LISTAGG at all?
SELECT LEGAL_ENTITY_ID,
(
SELECT COUNT(1)
FROM LE_MERGE_DDC_MAPPING
WHERE FLDNM IS NULL
) as Grandtotals
FROM V_VBA_DDCR_MAIN
WHERE LEGAL_ENTITY_ID=6000132;
(Since you are filtering on a single LEGAL_ENTITY_ID you don't need the final GROUP BY)
Are you sure there shouldn't be some sort of join condition between the two tables?
I'm struggling writing PL/SQL (I'm new to PL/SQL) and I'm not sure how to structure SQL and loops for something like this.
I have 128 lines of SQL to create something like the following cursor:
ID Course Grade Attend? Date
123 MATH091 B Y 5/15
123 BIOL101 F N 3/10
123 ENGL201 W Y 1/2
456 MATH091 A Y 5/16
456 CHEM101 C Y 5/16
456 POLS301 NULL NULL NULL
With each ID, I need to several comparisons across the courses (e.g. which has the latest date, or were all courses attended). These comparisons need to be done in a certain order so that when they hit one that is true, they are flagged with a code and excluded from subsequent comparisons.
For example:
All courses attended? If true, output as attended and remove from next steps.
Find and store the latest date with a passing grade.
Find and store the latest date with a non-passing grade.
Is the later date after a course with a null grade? If true, output as coming back and remove from next steps.
Etc.
Each condition can be easily written in a SQL, but I don't know/understand the appropriate structure to loop through this process.
Is there syntax that can accomplish this easily?
We're on Oracle 11g and we do not have permissions to write to a temporary table.
I don't think you need PL/SQL for this. Except for the "unknown" requirement "etc." this can all be done in a single SQL statement:
Something like:
select id, course, grade, attended, attendance_date,
count(distinct case when attended = 'Y' then course end) over (partition by id) courses_attended,
count(distinct course) over () as total_courses,
case
when count(distinct case when attended = 'Y' then course end) over (partition by id) = count(distinct course) over () then 'yes'
else 'no'
end as all_courses_attended,
max(case when attended <> 'F' then attendance_date else null end) over (partition by id) as latest_passing_date,
max(case when attended = 'F' then attendance_date else null end) over (partition by id) as latest_non_passing_date
from attendees
order by id;
Btw: the attended column is not necessary if you have an attendance_date. If that date is not NULL than obviously the student attended the course. Otherwise she/he didn't.
Of course I have no idea what the "etc." steps should do though....
SQLFiddle example: http://sqlfiddle.com/#!4/e7c95/1
Suppose this is my table:
ID STRING
1 'ABC'
2 'DAE'
3 'BYYYYYY'
4 'H'
I want to select all rows that have at least one of the characters in the STRING column somewhere in another row's STRING variable.
For example, 1 and 2 have an A in common and 1 ad 3 have a B in common, but 4 does not have any characters in common with any of the other rows. So my query should return only the first three lines.
I don't need to know with which line it matched.
Thanks!
#A.B.Cade : Good solution but could be done without any distinct nor join.
SELECT * FROM test t1
WHERE EXISTS
(
SELECT * FROM test t2
WHERE t1.id<>t2.id AND
regexp_like(t1.string, '['|| replace(t2.string, '.[]', '\.\[\]')||']')
)
The query won't compare the string with extra rows since it'll stop the comparison as soon as 1 match is found for the current row...
See fiddle.
#GolezTrol's answer is a good one, but here is another approach:
select distinct t1."ID", t1."STRING"
from table1 t1, table1 t2
where t1."ID" <> t2."ID"
and regexp_like(t1."STRING", '['|| t2."STRING"||']')
First take a cartessian product of the table
Then make sure your not comparing the same string to itself
then create a regexp from one string for comparing to the other - [<string1>] means that the string must contain one of the letters in the [ ] which are all from string1
Here is a fiddle
Like this:
select distinct
id, name
from
(select distinct
x.id,
x.NAME,
length(x.NAME) as leng,
substr(x.name, level, 1) as namechar
from
YourTable x
start with
level = 0
connect by
level <= length(x.name)) y
where
exists
(select
'x'
from
YourTable z
where
instr(z.name, y.namechar) > 0 and
z.id <> y.id)
order by
id
What it does:
First, (inner select) use the table with a number generator that returns a number for each letter in the name. Now each record in YourTable is returned Length(Name) times, each with another number. That generated number is used to isolate that letter (substr).
Then (subselect in top level where clause) check if records exist that contain that isolated letter. Distinct is needed, because records are returned more than once if more than one letter matches. You could add namechar to the outer select field list to see the letter that match.
For example, I have a table tbl like
values
10
20
30
40
on this table by the condition I have GROUP BY like this:
SELECT ???
FROM tbl
GROUP BY values
I need to check that group has some value, for example 30
UPD:
In real task a have a table with many columns and other operations on them and in one column i need to check whether value in every group of this column.
UPD2:
I need something like this:
select
min(created_timestamp),
max(resource_id),
max(price),
CASE WHEN event_type has (1704 or 1701 or 1703) THEN return found value END
CASE WHEN event_type has (1707) THEN return 1707 END
from subscriptions
group by guid
SELECT
MIN(created_timestamp),
MAX(resource_id),
MAX(price),
MIN(CASE WHEN event_type IN (1704, 1701, 1703)
THEN found_value
WHEN event_type = 1707
THEN 1707
ELSE NULL
END)
FROM subscriptions
GROUP BY guid ;
I did not get what you have in the select clause .. but if you want to see the values also in the out put when you run the group by query try this
select function(), values from tbl group by values
function() -- could be any function like -- count or sum
and if you want only specific to value 30 .. then add a where clause values = 30.
You dont need to use group by clause if your aim is to find if some value exists.
Use this method if you also consider the performance.
SELECT DECODE (COUNT(1),0,'Not Exist','Yes has some values')
FROM dual
WHERE EXISTS ( SELECT 1
FROM tbl
WHERE VALUES='&Your_Value_To_Check'
)