I've got the table:
create table example (id number, image varchar2(10));
With 2 rows:
insert into example (24, 'pippo');
insert into example (35,'pluto');
The query is:
select max(case when id=24 then image end) as col1,
max(case when id=35 then image end) as col2
from example;
This works perfectly fine with column "image" as varchar2! The problem is that the column is a BLOB.
How can I produce the same output?
Take in mind that I need to pull out of the table 28 images (so 28 columns and one row).
Still not clear why you need the result in columns and not rows... perhaps you only think you do? Alex asked you the most important question: Who/what will call this and consume the results? How is the result set used in further processing? It is possible you don't actually need the results in columns.
In any case, you can use Alex's suggestion of having 28 subquery expressions. If your concern is with performance, you can first select into a CTE (a WITH clause), whose result set will have just 28 rows - and then write the subquery expressions against the CTE. Something like this:
with prep ( id, blob_col ) as (
select id, blob_col from base_table where id in (24, 35, ... )
)
select
(select blob_col from prep where id = 24) as col_1,
(select blob_col from prep where id = 35) as col_2,
...
from dual
;
Related
I'm trying to take value from a non-empty row and overwrite it in the subsequent rows until another non-empty row appears and then write that in the subsequent rows. Coming from ABAP Background, I'm not sure how to accomplish this in HANA SQL Script. Here's a picture to show what the data looks like.
Basically 'Doe, John' should be overwritten into all the empty rows until 'Doe, Jane' appears and then 'Doe, Jane' should be overwritten into empty rows until another name appears.
My idea is to store the non-empty row in a local variable, but I haven't had much success so far. Here's my code:
tempTab1 = SELECT
CASE WHEN EMPLOYEE <> ''
THEN lv_emp = EMPLOYEE
ELSE EMPLOYEE
END AS EMPLOYEE,
FROM :tempTab;
In general, rows in dataset are unordered until you explicitly specify ORDER BY part of SQL. If you observe some order it may be a side-effect and can vary. So first of all you have to explicitly create a row number column (assume it's name is RECORD).
Then you should go this way:
Select only rows with non-empty data in column.
Use LEAD(RECORD) over(order by RECORD) to identify the next non-empty record number.
Join your source dataset to dataset defined on step 3 on between condition for RECORD field.
with a as (
select 1 as record, 'Val1' as field1 from dummy union
select 2 as record, '' as field1 from dummy union
select 3 as record, '' as field1 from dummy union
select 4 as record, 'Val2' as field1 from dummy union
select 5 as record, '' as field1 from dummy union
select 6 as record, '' from dummy union
select 7 as record, '' from dummy union
select 8 as record, 'Val3' as field1 from dummy
)
, fill_base as (
select field1, record, lead(record, 1, record) over(order by record asc) as next_record
from a
where field1 <> '' and field1 is not null
)
select
a.record
, case
when a.field1 = '' or a.field1 is null
then f.field1
else a.field1
end as field1
, a.field1 as field1_original
from a
left join fill_base as f
on a.record > f.record
and a.record < f.next_record
The performance in HANA may be bad in some cases since it process window functions very bad.
Here is another more elegant solution with two nested window functions than does not force you to write multiple selects for each column: How to make LAG() ignore NULLS in SQL Server?
You can use window aggregate function LAST_VALUE to achieve the imputation of missing values.
Sample Data
CREATE TABLE sample (id integer, sort integer, value varchar(10));
INSERT INTO sample VALUES (4711, 1, 'Hello');
INSERT INTO sample VALUES (4712, 2, null);
INSERT INTO sample VALUES (4713, 3, null);
INSERT INTO sample VALUES (4714, 4, 'World');
INSERT INTO sample VALUES (4715, 5, null);
INSERT INTO sample VALUES (4716, 6, '!');
Generate a new column with imputed values
SELECT base.*, LAST_VALUE(fill.value ORDER BY fill.sort) AS value_imputed
FROM sample base
LEFT JOIN sample fill ON fill.sort <= base.sort AND fill.value IS NOT NULL
GROUP BY base.id, base.sort, base.value
ORDER BY base.id, base.sort
Result
Note that sort could be anything determining the order (e.g. a timestamp).
I want to add the values of two columns displayed and display as 1 column name.
This is the output I'm getting,
ID Total
Apple 10
RawApple 10
Mango 10
RawMango 10
I want the output as
ID Total
Apples 20
Mangoes 20
If the issue is removing the first three characters -- if they are "Raw" -- then you can do:
select (case when id like 'Raw%' then stuff(id, 1, 3, '') else id end) as id,
sum(total)
from t
group by (case when id like 'Raw%' then stuff(id, 1, 3, '') else id end);
If you want to replace specific values with other values, I would suggest an in-query lookup table:
select coalesce(v.new_id, t.id) as id, sum(total)
from t left join
(values ('RawApple', 'Apple'),
('RawMango', 'Mango')
) v(id, new_id)
on t.id = v.id
group by coalesce(v.new_id, t.id);
If we can assume that the name of the fruit is after the prefix, and the prefix ends with a hyphen (-), then we can use STUFF to remove the prefix and then aggregate:
WITH VTE AS(
SELECT *
FROM (VALUES('Apple',10),
('Raw-Apple',10),
('Mango',10),
('Raw-Mango',10))V(ID,Total))
SELECT S.ID,
SUM(V.Total) AS Total
FROM VTE V
CROSS APPLY(VALUES(STUFF(V.ID,1,CHARINDEX('-',V.ID),'')))S(ID)
GROUP BY S.ID;
Note I don't change the names of the fruits to the plural, as depending on the fruit changes what the plural is. You'll need a dictionary table to store what the plural of the fruit is and then `JOIN to that. So a table that looks like this:
CREATE TABLE dbo.FruitPlural (Fruit varchar(20), Plural varchar(20));
INSERT INTO dbo.FruitPlural
VALUES ('Apple','Apples'),
('Mango','Mangoes'),
('Strawberry','Strawberries'),
...;
Note, this answer was invalidated due to the OP moving the goal posts due to the sample data not being representative of their actual data, however, I am leaving here as it may help future users.
I am creating a volatile table and trying to insert rows to the table. I can upload one row like below...
create volatile table Example
(
ProductID VARCHAR(15),
Price DECIMAL (15,2)
)
on commit preserve rows;
et;
INSERT INTO Example
Values
('Steve',4);
However, when I try to upload multiple I get the error:
"Syntax error: expected something between ')' and ','."
INSERT INTO Example
Values
('Steve',4),
('James',8);
As Gordon said, Teradata doesn't support VALUES with multiple rows (and the UNION ALL will fail because of the missing FROM.
You can utilize a Multi Statement Request (MSR) instead:
INSERT INTO Example Values('Steve',4)
;INSERT INTO Example Values('James',8)
;
If it's a BTEQ job the Inserts are submitted as one block after the final semicolon (when there's a new command starting on the same line it's part of the MSR). In SQL Assistant or Studio you must submit it using F9 instead of F5.
I don't think Teradata supports the multiple row values syntax. Just use select:
INSERT INTO Example(ProductId, Price)
WITH dual as (SELECT 1 as x)
SELECT 'Steve' as ProductId, 4 as Price FROM dual UNION ALL
SELECT 'James' as ProductId, 8 as Price FROM dual;
CTE syntax (working):
insert into target_table1 (col1, col2)
with cte as (select 1 col1)
select 'value1', 'value2' from cte
union all
select 'value1a', 'value2a' from cte
;
CTE Syntax not working in Teradata
(error: expected something between ")" and the "insert" keyword)
with cte as (select 1 col1)
insert into target_table1 (col1, col2)
select 'value1', 'value2' from cte
union all
select 'value1a', 'value2a' from cte
;
I found a solution for this via RECURSIVE. It goes like this:-
INSERT INTO table (col1, col2)
with recursive table (col1, col2) as
(select 'val1','val2' from table) -- 1
select 'val1','val2' from table -- 2
union all select 'val3','val4' from table
union all select 'val5','val6' from table;
Data of line 1 does not get inserted (but you need this line). Starting from line 2, the data you enter for val1, val2 etc. gets inserted into the respective columns. Use as many UNION ALLs' as many rows you want to insert. Hope this helps :)
At least in our version of Teradata, we are not able to use an insert statement with a CTE. Instead, find a real table (preferably small in size) and do a top 1.
Insert Into OtherRealTable(x, y)
Select top 1
'x' as x,
'y' as y
FROM RealTable
create table dummy as (select '1' col1) with data;
INSERT INTO Student
(Name, Maths, Science, English)
SELECT 'Tilak', 90, 40, 60 from dummy union
SELECT 'Raj', 30, 20, 10 from dummy
;
yes you can try this.
INSERT INTO Student
SELECT (Name, Maths, Science, English) FROM JSON_Table
(ON (SELECT 1 id,cast('{"DataSet" : [
{"s":"m", "Name":"Tilak", "Maths":"90","Science":"40", "English":"60" },
{"s":"m", "Name":"Raj", "Maths":"30","Science":"20", "English":"10" }
]
}' AS json ) jsonCol)
USING rowexpr('$.DataSet[*]')
colexpr('[{"jsonpath":"$.s","type":"CHAR(1)"},{"jsonpath":"$.Name","type":"VARCHAR(30)"}, {"jsonpath":"$.Maths","type":"INTEGER"}, {"jsonpath":"$.Science","type":"INTEGER"}, {"jsonpath":"$.English","type":"INTEGER"}]')
) AS JT(id,State,Name, Maths, Science, English)
I'm new to teradata. I want to insert numbers 1 to 1000 into the table test_seq, which is created as below.
create table test_seq(
seq_id integer
);
After searching on this site, I came up with recusrive query to insert the numbers.
insert into test_seq(seq_id)
with recursive cte(id) as (
select 1 from test_dual
union all
select id + 1 from cte
where id + 1 <= 1000
)
select id from cte;
test_dual is created as follows and it contains just a single value. (something like DUAL in Oracle)
create table test_dual(
test_dummy varchar(1)
);
insert into test_dual values ('X');
But, when I run the insert statement, I get the error, Failure 2616 Numeric overflow occurred during computation.
What did I do wrong here? Isn't the integer datatype enough to hold numeric value 1000?
Also, is there a way to write the query so that i can do away with test_dual table?
When you simply write 1 the parser assigns the best matching datatype to it, which is a BYTEINT. The valid range of values for BYTEINT is -128 to 127, so just add a typecast to INT :-)
Usually you don't need a dummy DUAL table in Teradata, "SELECT 1;" is valid, but in some cases the parser still insists on a FROM (don't ask me why). This trick should work:
SEL * FROM (SELECT 1 AS x) AS dt;
You can create a view on this:
REPLACE VIEW oDUAL AS SELECT * FROM (SELECT 'X' AS dummy) AS dt;
Explain "SELECT 1 FROM oDUAL;" is a bit stupid, so a real table might be better. But to get efficient access (= single AMP/single row) it must be defined as follows:
CREATE TABLE dual_tbl(
dummy VARCHAR(1) CHECK ( dummy = 'X')
) UNIQUE PRIMARY INDEX(dummy); -- i remember having fun when you inserted another row in Oracle's DUAL :_)
INSERT INTO dual_tbl VALUES ('X');
REPLACE VIEW oDUAL AS SELECT dummy FROM dual_tbl WHERE dummy = 'X';
insert into test_seq(seq_id)
with recursive cte(id) as (
select cast(1 as int) from oDUAL
union all
select id + 1 from cte
where id + 1 <= 1000
)
select id from cte;
But recursion is not an appropriate way to get a range of numbers as it's sequential and always an "all-AMP step" even if it the data resides on a single AMP like in this case.
If it's less than 73414 values (201 years) better use sys_calendar.calendar (or any other table with a known sequence of numbers) :
SELECT day_of_calendar
FROM sys_calendar.CALENDAR
WHERE day_of_calendar BETWEEN 1 AND 1000;
Otherwise use CROSS joins, e.g. to get numbers from 1 to 1,000,000:
WITH cte (i) AS
( SELECT day_of_calendar
FROM sys_calendar.CALENDAR
WHERE day_of_calendar BETWEEN 1 AND 1000
)
SELECT
(t2.i - 1) * 1000 + t1.i
FROM cte AS t1 CROSS JOIN cte AS t2;
Let's say I have a boolean field in a database table and I want to get a tally of how many are 1 and how many are 0. Currently I am doing:
SELECT 'yes' AS result, COUNT( * ) AS num
FROM `table`
WHERE field = 1
UNION
SELECT 'no' AS result, COUNT( * ) AS num
FROM `table`
WHERE field = 0;
Is there an easier way to get the result so that even if there are no false values I will still get:
----------
|yes | 3 |
|no | 0 |
----------
One way would be to outer join onto a lookup table. So, create a lookup table that maps field values to names:
create table field_lookup (
field int,
description varchar(3)
)
and populate it
insert into field_lookup values (0, 'no')
insert into field_lookup values (1, 'yes')
now the next bit depends on your SQL vendor, the following has some Sybase (or SQL Server) specific bits (the outer join syntax and isnull to convert nulls to zero):
select description, isnull(num,0)
from (select field, count(*) num from `table` group by field) d, field_lookup fl
where d.field =* fl.field
you are on the right track, but the first answer will not be correct. Here is a solution that will give you Yes and No even if there is no "No" in the table:
SELECT 'Yes', (SELECT COUNT(*) FROM Tablename WHERE Field <> 0)
UNION ALL
SELECT 'No', (SELECT COUNT(*) FROM tablename WHERE Field = 0)
Be aware that I've checked Yes as <> 0 because some front end systems that uses SQL Server as backend server, uses -1 and 1 as yes.
Regards
Arild
This will result in two columns:
SELECT SUM(field) AS yes, COUNT(*) - SUM(field) AS no FROM table
Because there aren't any existing values for false, if you want to see a summary value for it - you need to LEFT JOIN to a table or derived table/inline view that does. Assuming there's no TYPE_CODES table to lookup the values, use:
SELECT x.desc_value AS result,
COALESCE(COUNT(t.field), 0) AS num
FROM (SELECT 1 AS value, 'yes' AS desc_value
UNION ALL
SELECT 2, 'no') x
LEFT JOIN TABLE t ON t.field = x.value
GROUP BY x.desc_value
SELECT COUNT(*) count, field FROM table GROUP BY field;
Not exactly same output format, but it's the same data you get back.
If one of them has none, you won't get that rows back, but that should be easy enough to check for in your code.