I am using oracle PL/SQL.
I am trying to compare column values with LAG function.
Following is the statement:
decode(LAG(col1,1) OVER (ORDER BY col3),col1,'No Change','Change_Occured') Changes
As for first row, LAG will always compare with the previous empty row. So for my query the first row of column 'Changes' is always showing the value as Change_Occured when in fact no change has happened. Is there any way to handle this scenario ?
Assume this table:
| col1 | col2 |
| 2 | 3 |
| 2 | 6 |
| 2 | 7 |
| 2 | 9 |
Each row of col1 is compared with previous value so result will be
| col1 | col2 | Changes |
| 2 | 3 | Change_occured |
| 2 | 9 | No Change |
| 2 | 5 | No Change |
| 2 | 8 | No Change |
So how should I handle the first row of column Changes
The syntax for LAG Analytic function is:
LAG (value_expression [,offset] [,default]) OVER ([query_partition_clause] order_by_clause)
default - The value returned if the offset is outside the scope of the window. The default value is NULL.
SQL> WITH sample_data AS(
2 SELECT 2 col1, 3 col2 FROM dual UNION ALL
3 SELECT 2 col1, 6 col2 FROM dual UNION ALL
4 SELECT 2 col1, 7 col2 FROM dual UNION ALL
5 SELECT 2 col1, 9 col2 FROM dual
6 )
7 -- end of sample_data mimicking real table
8 SELECT col1, LAG(col1,1) OVER (ORDER BY col2) changes FROM sample_data;
COL1 CHANGES
---------- ----------
2
2 2
2 2
2 2
Therefore, in the DECODE expression you are comparing the NULL value with a real value and it is evaluated as Change_Occurred
You could use the default value as the column value itself:
DECODE(LAG(col1,1, col1) OVER (ORDER BY col2),col1,'No Change','Change_Occured') Changes
For example,
SQL> WITH sample_data AS(
2 SELECT 2 col1, 3 col2 FROM dual UNION ALL
3 SELECT 2 col1, 6 col2 FROM dual UNION ALL
4 SELECT 2 col1, 7 col2 FROM dual UNION ALL
5 SELECT 2 col1, 9 col2 FROM dual
6 )
7 -- end of sample_data mimicking real table
8 SELECT col1,
9 DECODE(
10 LAG(col1,1, col1) OVER (ORDER BY col2),
11 col1,
12 'No Change',
13 'Change_Occured'
14 ) Changes
15 FROM sample_data;
COL1 CHANGES
---------- --------------
2 No Change
2 No Change
2 No Change
2 No Change
SQL>
May be:
decode(LAG(col1,1, col1) OVER (ORDER BY col3),col1,'No Change','Change_Occured') Changes
The optional default value is returned if the offset goes beyond the scope of the window. If you do not specify default, then its default is null.
Related
I'm trying to find totals for each number in the range of 1 to 7. But the data contains different combinations of these numbers. For e.g. 1; 2; 3,7; 1,2,3 and so on. I want to find the total number of times each number pops up. What I essentially want is a code for SQLite that's goes like:
select <fields>, count(*)
from tablexyz
where <field> contains '2' (and '3','4',... individually)
When I input "where like '2%'" and such, it only gives me all series that start with 2 but negates series that starts with 1 but contains 2.
Any help would be appreciated!
I want to find the total number of times each number pops up
Your sample code and the solution you say you want don't exactly align. The closest I can think of is
with t (txt) as -- a sample record from your table
(select '1; 2; 3,7; 1,2,3'),
t2 (num) as -- a lookup table we can create for range of numbers 1-7
(select 1 union all
select 2 union all
select 3 union all
select 4 union all
select 5 union all
select 6 union all
select 7)
select t2.num, length(t.txt) - length(replace(t.txt,t2.num,'')) as num_occurence
from t2
left join t on t.txt like '%' || t2.num || '%'
Outputs
+-----+---------------+
| num | num_occurence |
+-----+---------------+
| 1 | 2 |
| 2 | 2 |
| 3 | 2 |
| 4 | NULL |
| 5 | NULL |
| 6 | NULL |
| 7 | 1 |
+-----+---------------+
Demo
Using the solution below, you can build a "table" of the numbers 1 to 7, then join it to your source data table to count if the number occurs in that row, then sum it together.
Query
WITH
sample_data (nums)
AS
(SELECT '1,2,3,4,5,6'
UNION ALL
SELECT '3,4,5,6'
UNION ALL
SELECT '1,2,7,6'
UNION ALL
SELECT '6' ),
search_nums (search_num)
AS
(VALUES(1)
UNION ALL
SELECT search_num+1 FROM search_nums WHERE search_num<7)
select search_num, sum(count_of_num) from (
SELECT s.nums,
n.search_num,
case
instr(s.nums, n.search_num)
when 0 then 0
else 1
end as count_of_num
FROM sample_data s, search_nums n
) group by search_num;
Result
search_num sum(count_of_num)
1 2
2 2
3 2
4 2
5 2
6 4
7 1
I am learning to use SQL and got the problem that I cant find a solution to add two select statements.
I tried it with union and the function sum(). I also tried to find a similar question here - without success.
select *
from (select 6,4,2,4,7,2,7
from dual
union
select 3,8,9,2,7,4,5
from dual)
I tried this but it shows me two rows with the numbers in the code.
I want the result of the rows in one single row, like:
9,12,11,6,14,6,12
You must alias the columns of the 1st query, and use sum() to aggregate on each of the columns:
select
sum(col1) sum1, sum(col2) sum2, sum(col3) sum3, sum(col4) sum4, sum(col5) sum5, sum(col6) sum6, sum(col7) sum7
from (
select 6 col1, 4 col2, 2 col3, 4 col4, 7 col5, 2 col6, 7 col7 from dual
union
select 3, 8, 9, 2, 7, 4, 5 from dual
)
See the demo.
Results:
SUM1 | SUM2 | SUM3 | SUM4 | SUM5 | SUM6 | SUM7
---: | ---: | ---: | ---: | ---: | ---: | ---:
9 | 12 | 11 | 6 | 14 | 6 | 12
First of all Union doesnt add data but combine rows and that too when the data to be unioned is having same no of columns and same type.
Your query is irrelevant and adding numerics like this is a bad practice and is off logic.
1. Select 6+3,....,.. from table
2. Select col1+col2 from table
where col1 in (6,4,2,4,7,2,7) and col2 in
(3,8,9,2,7,4,5)
As you could see the second query makes sense but first query doesnt.
I am trying to replicate a workplace scenario. The sqlfiddle for Oracle db is not working so I couldn't recreate the table.
Say I have a table like below
Table1
+----+------+
| ID | Col1 |
+----+------+
| 1 | A |
| 2 | B |
| 3 | C |
+----+------+
Now we run a query with where condition. The in clause for where is passed by user and run time and can change.
Suppose user inputs 1,2,4,5
So the SQL will be like
select t.* from Table1 t where t.id in (1,2,4,5);
The result of this query will be
+----+------+
| ID | Col1 |
+----+------+
| 1 | A |
| 2 | B |
+----+------+
Now output I am expecting should be something like below
+----+---------+------+
| ID | ErrCode | Col1 |
+----+---------+------+
| 1 | 0 | A |
| 2 | 0 | B |
| 4 | 404 | |
| 5 | 404 | |
+----+---------+------+
As 3 was not entered by user, we will not return it. But for 4 and 5, there is no record in our table, so I want to create another dummy column which will contain error code. The data columns should be null.
It is not mandatory that the user input should go to in clause. We can use it anywhere in the query.
I am thinking of some way of splitting the input id and use them as rows. Then use them to do left join with Table1 to find the records which exists and doesn't exist in Table1 and use case on that to decide among 0 or 404 as error code.
Appreciate any other way we can do it by query.
Here it goes
SQL> WITH table_filter AS
2 (SELECT regexp_substr(txt, '[^,]+', 1, LEVEL) id
3 FROM (SELECT '1,2,4,5' AS txt FROM dual) -- User input here
4 CONNECT BY regexp_substr(txt, '[^,]+', 1, LEVEL) IS NOT NULL),
5 table1 AS -- Sample data
6 (SELECT 1 id,
7 'A' col1
8 FROM dual
9 UNION ALL
10 SELECT 2,
11 'B'
12 FROM dual
13 UNION ALL
14 SELECT 3,
15 'C'
16 FROM dual)
17 SELECT f.id,
18 CASE
19 WHEN t.id IS NULL THEN
20 404
21 ELSE
22 0
23 END AS err_code,
24 t.col1
25 FROM table_filter f
26 LEFT OUTER JOIN table1 t
27 ON t.id = f.id;
ID ERR_CODE COL1
---------------------------- ---------- ----
1 0 A
2 0 B
5 404
4 404
SQL>
Oracle Setup:
CREATE TABLE Table1 ( id, col1 ) AS
SELECT 1, 'A' FROM DUAL UNION ALL
SELECT 2, 'B' FROM DUAL;
Query:
SELECT i.COLUMN_VALUE AS id,
NVL2( t.col1, 0, 404 ) AS ErrCode,
t.col1
FROM TABLE( SYS.ODCINUMBERLIST( 1, 2, 4, 5 ) ) i
LEFT OUTER JOIN
Table1 t
ON ( i.COLUMN_VALUE = t.id );
Output:
ID ERRCODE COL1
-- ------- ----
1 0 A
2 0 B
4 404
5 404
The collection of ids can be built dynamically using PL/SQL or an external language and then passed as a bind variable. See my answer here for an example.
I have the following table:
crit_id | criterium | val1 | val2
----------+------------+-------+--------
1 | T01 | 9 | 9
2 | T02 | 3 | 5
3 | T03 | 4 | 9
4 | T01 | 2 | 3
5 | T02 | 5 | 1
6 | T03 | 6 | 1
I need to convert the values in 'criterium' into columns as 'cross product' with val1 and val2. So the result has to lool like:
T01_val1 |T01_val2 |T02_val1 |T02_val2 | T03_val1 | T03_val2
---------+---------+---------+---------+----------+---------
9 | 9 | 3 | 5 | 4 | 9
2 | 3 | 5 | 1 | 6 | 1
Or to say differently: I need every value for all criteria to be in one row.
This is my current approach:
select
case when criterium = 'T01' then val1 else null end as T01_val1,
case when criterium = 'T01' then val2 else null end as T01_val2,
case when criterium = 'T02' then val1 else null end as T02_val1,
case when criterium = 'T02' then val2 else null end as T02_val2,
case when criterium = 'T03' then val1 else null end as T03_val1,
case when criterium = 'T03' then val2 else null end as T04_val2,
from crit_table;
But the result looks not how I want it to look like:
T01_val1 |T01_val2 |T02_val1 |T02_val2 | T03_val1 | T03_val2
---------+---------+---------+---------+----------+---------
9 | 9 | null | null | null | null
null | null | 3 | 5 | null | null
null | null | null | null | 4 | 9
What's the fastest way to achieve my goal?
Bonus question:
I have 77 criteria and seven different kinds of values for every criterium. So I have to write 539 case statements. Whats the best way to create them dynamically?
I'm working with PostgreSql 9.4
Prepare for crosstab
In order to use crosstab() function, the data must be reorganized. You need a dataset with three columns (row number, criterium, value). To have all values in one column you must unpivot two last columns, changing at the same time the names of criteria. As a row number you can use rank() function over partitions by new criteria.
select rank() over (partition by criterium order by crit_id), criterium, val
from (
select crit_id, criterium || '_v1' criterium, val1 val
from crit
union
select crit_id, criterium || '_v2' criterium, val2 val
from crit
) sub
order by 1, 2
rank | criterium | val
------+-----------+-----
1 | T01_v1 | 9
1 | T01_v2 | 9
1 | T02_v1 | 3
1 | T02_v2 | 5
1 | T03_v1 | 4
1 | T03_v2 | 9
2 | T01_v1 | 2
2 | T01_v2 | 3
2 | T02_v1 | 5
2 | T02_v2 | 1
2 | T03_v1 | 6
2 | T03_v2 | 1
(12 rows)
This dataset can be used in crosstab():
create extension if not exists tablefunc;
select * from crosstab($ct$
select rank() over (partition by criterium order by crit_id), criterium, val
from (
select crit_id, criterium || '_v1' criterium, val1 val
from crit
union
select crit_id, criterium || '_v2' criterium, val2 val
from crit
) sub
order by 1, 2
$ct$)
as ct (rank bigint, "T01_v1" int, "T01_v2" int,
"T02_v1" int, "T02_v2" int,
"T03_v1" int, "T03_v2" int);
rank | T01_v1 | T01_v2 | T02_v1 | T02_v2 | T03_v1 | T03_v2
------+--------+--------+--------+--------+--------+--------
1 | 9 | 9 | 3 | 5 | 4 | 9
2 | 2 | 3 | 5 | 1 | 6 | 1
(2 rows)
Alternative solution
For 77 criteria * 7 parameters the above query may be troublesome. If you can accept a bit different way of presenting the data, the issue becomes much easier.
select * from crosstab($ct$
select
rank() over (partition by criterium order by crit_id),
criterium,
concat_ws(' | ', val1, val2) vals
from crit
order by 1, 2
$ct$)
as ct (rank bigint, "T01" text, "T02" text, "T03" text);
rank | T01 | T02 | T03
------+-------+-------+-------
1 | 9 | 9 | 3 | 5 | 4 | 9
2 | 2 | 3 | 5 | 1 | 6 | 1
(2 rows)
DECLARE #Table1 TABLE
(crit_id int, criterium varchar(3), val1 int, val2 int)
;
INSERT INTO #Table1
(crit_id, criterium, val1, val2)
VALUES
(1, 'T01', 9, 9),
(2, 'T02', 3, 5),
(3, 'T03', 4, 9),
(4, 'T01', 2, 3),
(5, 'T02', 5, 1),
(6, 'T03', 6, 1)
;
select [T01] As [T01_val1 ],[T01-1] As [T01_val2 ],[T02] As [T02_val1 ],[T02-1] As [T02_val2 ],[T03] As [T03_val1 ],[T03-1] As [T03_val3 ] from (
select T.criterium,T.val1,ROW_NUMBER()OVER(PARTITION BY T.criterium ORDER BY (SELECT NULL)) RN from (
select criterium, val1 from #Table1
UNION ALL
select criterium+'-'+'1', val2 from #Table1)T)PP
PIVOT (MAX(val1) FOR criterium IN([T01],[T02],[T03],[T01-1],[T02-1],[T03-1]))P
I agree with Michael's comment that this requirement looks a bit weird, but if you really need it that way, you were on the right track with your solution. It just needs a little bit of additional code (and small corrections wherever val_1 and val_2 where mixed up):
select
sum(case when criterium = 'T01' then val_1 else null end) as T01_val1,
sum(case when criterium = 'T01' then val_2 else null end) as T01_val2,
sum(case when criterium = 'T02' then val_1 else null end) as T02_val1,
sum(case when criterium = 'T02' then val_2 else null end) as T02_val2,
sum(case when criterium = 'T03' then val_1 else null end) as T03_val1,
sum(case when criterium = 'T03' then val_2 else null end) as T03_val2
from
crit_table
group by
trunc((crit_id-1)/3.0)
order by
trunc((crit_id-1)/3.0);
This works as follows. To aggregate the result you posted into the result you would like to have, the first helpful observation is that the desired result has less rows than your preliminary one. So there's some kind of grouping necessary, and the key question is: "What's the grouping criterion?" In this case, it's rather non-obvious: It's criterion ID (minus 1, to start counting with 0) divided by 3, and truncated. The three comes from the number of different criteria. After that puzzle is solved, it is easy to see that for among the input rows that are aggregated into the same result row, there is only one non-null value per column. That means that the choice of aggregate function is not so important, as it is only needed to return the only non-null value. I used the sum in my code snippet, but you could as well use min or max.
As for the bonus question: Use a code generator query that generates the query you need. The code looks like this (with only three types of values to keep it brief):
with value_table as /* possible kinds of values, add the remaining ones here */
(select 'val_1' value_type union
select 'val_2' value_type union
select 'val_3' value_type )
select contents from (
select 0 order_id, 'select' contents
union
select row_number() over () order_id,
'max(case when criterium = '''||criterium||''' then '||value_type||' else null end) '||criterium||'_'||value_type||',' contents
from crit_table
cross join value_table
union select 9999999 order_id,
' from crit_table group by trunc((crit_id-1)/3.0) order by trunc((crit_id-1)/3.0);' contents
) v
order by order_id;
This basically only uses a string template of your query and then inserts the appropriate combinations of values for the criteria and the val-columns. You could even get rid of the with-clause by reading column names from information_schema.columns, but I think the basic idea is clearer in the version above. Note that the code generated contains one comma too much directly after the last column (before the from clause). It's easier to delete that by hand afterwards than correcting it in the generator.
I'm dealing with some legacy data in an Oracle table and have the following
--------------------------------------------
| RefNo | ID |
--------------------------------------------
| FOO/BAR/BAZ/AAAAAAAAAA | 1 |
| FOO/BAR/BAZ/BBBBBBBBBB | 1 |
| FOO/BAR/BAZ/CCCCCCCCCC | 1 |
| FOO/BAR/BAZ/DDDDDDDDDD | 1 |
--------------------------------------------
For each of the /FOO/BAR/BAZ/% records I want to make the ID a Unique incrementing number.
Is there a method to do this in SQL?
Thanks in advance
EDIT
Sorry for not being specific. I have several groups of records /FOO/BAR/BAZ/, /FOO/ZZZ/YYY/. The same transformation needs to occur for each of these other (example) groups. The recnum can't be used I want ID to start from 1, incrementing, for each group of records I have to change.
Sorry for making a mess of my first post. Output should be
--------------------------------------------
| RefNo | ID |
--------------------------------------------
| FOO/BAR/BAZ/AAAAAAAAAA | 1 |
| FOO/BAR/BAZ/BBBBBBBBBB | 2 |
| FOO/BAR/BAZ/CCCCCCCCCC | 3 |
| FOO/BAR/BAZ/DDDDDDDDDD | 4 |
| FOO/ZZZ/YYY/AAAAAAAAAA | 1 |
| FOO/ZZZ/YYY/BBBBBBBBBB | 2 |
--------------------------------------------
Let's try something like this(Oracle version 10g and higher):
SQL> with t1 as(
2 select 'FOO/BAR/BAZ/AAAAAAAAAA' as RefNo, 1 as ID from dual union all
3 select 'FOO/BAR/BAZ/BBBBBBBBBB', 1 from dual union all
4 select 'FOO/BAR/BAZ/CCCCCCCCCC', 1 from dual union all
5 select 'FOO/BAR/BAZ/DDDDDDDDDD', 1 from dual union all
6 select 'FOO/ZZZ/YYY/AAAAAAAAAA', 1 from dual union all
7 select 'FOO/ZZZ/YYY/BBBBBBBBBB', 1 from dual union all
8 select 'FOO/ZZZ/YYY/CCCCCCCCCC', 1 from dual union all
9 select 'FOO/ZZZ/YYY/DDDDDDDDDD', 1 from dual
10 )
11 select row_number() over(partition by ComPart order by DifPart) as id
12 , RefNo
13 From (select regexp_substr(RefNo, '[[:alpha:]]+$') as DifPart
14 , regexp_substr(RefNo, '([[:alpha:]]+/)+') as ComPart
15 , RefNo
16 , Id
17 from t1
18 ) q
19 ;
ID REFNO
---------- -----------------------
1 FOO/BAR/BAZ/AAAAAAAAAA
2 FOO/BAR/BAZ/BBBBBBBBBB
3 FOO/BAR/BAZ/CCCCCCCCCC
4 FOO/BAR/BAZ/DDDDDDDDDD
1 FOO/ZZZ/YYY/AAAAAAAAAA
2 FOO/ZZZ/YYY/BBBBBBBBBB
3 FOO/ZZZ/YYY/CCCCCCCCCC
4 FOO/ZZZ/YYY/DDDDDDDDDD
I think that actual updating the ID column wouldn't be a good idea. Every time you add new groups of data you would have to run the update statement again. The better way would be creating a view and you will see desired output every time you query it.
rownum can be used as an incrementing ID?
UPDATE legacy_table
SET id = ROWNUM;
This will assign unique values to all records in the table. This link contains documentation about Oracle Pseudocolumn.
You can run the following:
update <table_name> set id = rownum where descr like 'FOO/BAR/BAZ/%'
This is pretty rough and I'm not sure if your RefNo is a single value column or you just made it like that for simplicity.
select
sub.RefNo
row_number() over (order by sub.RefNo) + (select max(id) from TABLE),
from (
select FOO+'/'+BAR+'/'+BAZ+'/'+OTHER as RefNo
from TABLE
group by FOO+'/'+BAR+'/'+BAZ+'/'+OTHER
) sub