I have this table tbl_buku:
id_buku judul_buku tahun_buku
1 Bioogi 2010
2 Fisika 2010
3 Informatika 2012
4 Kimia 2012
I use query like this, but I am getting an error:
select case when t1.tahun_buku=t2.tahun_buku then ''
else t1.tahun_buku end tahun_buku,t1.judul_buku
from tbl_buku t1 left join tbl_buku t2
on t1.id_buku-1=t2.id_buku;
I want to show table like this:
tahun_buku judul_buku
2010 Biologi
Fisika
2012 Informatika
Kimia
How to achieve this?
I think the problem in your query is that tahun_buku is of datatype int and you are trying to select an empty string ('').
You have to workarounds:
Change tahun_buku to be varchar (2010,2012..will be consider as strings I dont know if it is ok)
Set:
select case when t1.tahun_buku=t2.tahun_buku then null else t1.tahun_buku end tahun_buku,t1.judul_buku
from tbl_buku t1 left join tbl_buku t2
on t1.id_buku-1=t2.id_buku;
Use the window function lag() to get values from the previous row.
Use NULL for "empty" values in a numeric column - like #apomene already suggested.
The empty string '' can only be used in character types like text or varchar.
Use NULLIF() in this particular case to substitute the NULL value.
SELECT NULLIF(lag(tahun_buku) OVER (ORDER BY tahun_buku, judul_buku)
, tahun_buku) AS tahun_buku
, judul_buku
FROM tbl_buku
ORDER BY tahun_buku, judul_buku;
Related
I have a SQL query, linking table 1 to table 2 via an inner join, containing this part in the select part of the statement:
select
table1.field1,
table2.field1,
CASE (table2.field1)
WHEN -2 THEN ''
ELSE table2.field2
END as table2Field2,
table3.field4
from...
I want to be able to return table2Field2 when it has a relevant value, ie: when the object represented in table2 is not null, so that table2.field1 does not have a value of -2. In this case, the value of table2Field2 should be blank instead of a meaningless value.
However, this returns 0 instead of the blank text. If I change this line:
WHEN -2 THEN ''
to this:
WHEN -2 THEN 'someText'
then it complains at me that it's trying to convert an int to a string, which I'm not. table2field1 is an int, but table2Field2 is a string, which is what we're actually returning here.
How do I state (even more specifically) in this query that I'm returning the string field as a string, and not something else as a string that isn't (a) a string, and (b) the thing I specified I'm returning please?
All suggestions welcome, many thanks in advance for any help :)
In a CASE expression, all of the possible return values must be of the same data type. As written, the expression is trying to return one string and one integer.
If you want an empty string for your first output, you can CAST or CONVERT your second output to a character type value:
select
table1.field1,
table2.field1,
CASE (table2.field1)
WHEN -2 THEN ''
ELSE CAST(table2.field2 AS varchar(12)) --< 12 will cover any value of integer.
END as table2Field2,
table3.field4
from...
Is it possible you have your as table2field2 in the wrong location?
maybe try:
select
table1.field1,
table2.field1,
CASE (table2.field1)
WHEN -2 THEN ''
ELSE table2.field2
END as table2Field2,
table3.field4
from...
Because you do not want to answer me what is the database you use then I have to do it like this hehehe:
SQL Server: DEMO
select
t.col1,
CASE
WHEN convert(char,t.col1) = '-2' THEN 'aaa'
ELSE convert(char,(t.col2))
END test
from Tab1 t;
Oracle DEMO
select
t.col1,
CASE
WHEN to_char(t.col1) = '-2' THEN 'aaa'
ELSE to_char(t.col2)
END test
from tab1 t;
I have the a query which looks similar to:
SELECT
s.cola, s.colb, t.colc, t.cold, u.cole, u.colf, u.colg, u.colh, u.coli, u.colj, u.colk, u.coll
FROM table1 s
INNER JOIN table2 t
ON s.colb = t.colc
INNER JOIN table3 u
ON u.colm = t.cold
WHERE cast(s.cola as date) between date '2017-11-06' and date '2017-11-10'
ORDER BY 3
I need to add a new column, called col_new, which is to be filled by either u.colm or u.coln. This column will have values from u.colm if that column starts with a number. Otherwise it will have values from u.coln. It is known that either u.coln or u.colm starts with a number, for each entry in table u.
I tried the following query to test if entries starting with a number can be identified or not:
SELECT CASE WHEN ISNUMERIC(SUBSTRING(LTRIM(colm), 1, 1)) = 1
THEN 'yes'
ELSE 'no'
END AS col_new
FROM table_u
It returned the error: Syntax error: expected something between '(' and the 'substring' keyword.
Kindly suggest a solution.
Edit:
Exact Error:
[Teradata Database] [3706] Syntax error: expected something between '(' and the 'substring' keyword.
Instead of isnumeric(), just do a comparison:
SELECT (CASE WHEN LEFT(LTRIM(colm), 1) BETWEEN '0' AND '9' THEN 'yes'
ELSE 'no'
END) AS col_new
FROM table_u;
LEFT() is a convenient shorthand for the first "n" characters of a string.
I have a requirement to move varchar column data to Numeric but with two conditions.
All the alphanumeric value should migrate as null
All the decimal values should go as it is.
I wrote the condition as WHERE data like '%[^0-9]%', it is working fine for all the records except for decimal.
Also I have values like .001 abcd, this has to be pass as null.
To summarize I need :
1) 1234 as 1234
2) 1.23 as 1.23
3) ABC as null
4) .ABC as null
There is by default function in SQL Server ISNUMERIC() so, first of all Check your data value by that function,
Select ISNUMERIC(DATA)
Whole query is written as below,
SELECT CASE WHEN ISNUMERIC(data)=1 THEN CAST(data as decimal(18,2))
ELSE NULL END as tData FROM DataTable
As per your question,first we have to convert with numeric with using case,which satisfies your first condition,another thing if the value is String than convert as NULL. In Above query both the condition has been taken care.
EDIT : If you are using SQL SERVER 2012 or higher version then use
TRY_PARSE(), then there will be no need to worry about using CASE too...
I have tried this,
SELECT TRY_PARSE('63.36' as decimal(18,2)) got result 63.36
and
SELECT TRY_PARSE('.' as decimal(18,2)) got result NULL
I think that this fits your spec. It is quite verbose, but hopefully it breaks down the conditions sufficiently that it's clearly doing the correct thing or, if it isn't, that it's easy enough to modify:
declare #t table (data varchar(30))
insert into #t(data) values
('1234'),
('1.23'),
('abc'),
('.abc'),
('+6000'),
('1.2.3')
select
CASE WHEN
Possible = 1 AND
(DecCheck = 0 OR
SingleDec = 1
) THEN
CONVERT(decimal(12,3),data)
END
from
#t t
cross apply
(select
--Only contains the correct characters
CASE WHEN not t.data like '%[^0-9.]%' THEN 1 ELSE 0 END as Possible,
--Contains a decimal point? (Needs more checks)
CASE WHEN CHARINDEX('.',t.data) > 0 THEN 1 ELSE 0 END as DecCheck,
CHARINDEX('.',t.data) as FirstDec --Where the first decimal point is
) p
cross apply
(select
CASE WHEN DecCheck = 1 THEN
--Only contains one decimal point
CASE WHEN LEN(data) = FirstDec + CHARINDEX('.',REVERSE(data)) - 1
THEN 1
ELSE 0 END
ELSE 0 END as SingleDec
) d
Results:
data
------------------------------ ---------------------------------------
1234 1234.000
1.23 1.230
abc NULL
.abc NULL
+6000 NULL
1.2.3 NULL
I.e. one additional check you may want to use is that a decimal cannot be the first or last character in the string. That is easy enough to do by adding those additional checks into the first CASE for the SingleDec column.
try ISNUMERIC function,
SELECT ISNUMERIC('abc')
SELECT ISNUMERIC('1.23')
On SQL Server (Version 2012, 11.0.5343)
SELECT
CASE WHEN ISNUMERIC('.') = 1 THEN <Field> ELSE 0 END
FROM
<Table>
works fine ...
Thre is A blog post.
Try following
SELECT
CASE
WHEN
ISNUMERIC(data + 'e0') = 1 THEN CAST(data AS decimal(18,2))
ELSE NULL END AS tData
FROM
DataTable
try ISNUMERIC function
DECLARE #MyTable TABLE(Val VARCHAR(100))
INSERT INTO #MyTable
VALUES
('1234')
,('1.23')
,('ABC')
,('.ABC')
,('MJA')
Select Val as OldValue,
Case
When ISNUMERIC(Val) = 1
then Cast(Val as numeric(18,2))
else null
end NewValue
From #MyTable
Output
OldValue NewValue
-----------------------------------------------------
1234 1234.00
1.23 1.23
ABC NULL
.ABC NULL
MJA NULL
(5 row(s) affected)
I'm struggling to understand how to check for a null value in a progress case expression. I want to see if a column exists and use that, if not use the fallback column. For example, William in first name would be over written by Bill in fn.special-char.
I've got the following query:
SELECT
"PUB"."NAME"."LAST-NAME" as LastName,
CASE fn."SPECIAL-CHAR"
WHEN is null THEN "PUB"."NAME"."FIRST-NAME"
ELSE fn."SPECIAL-CHAR"
END as FirstName
FROM "PUB"."NAME"
LEFT OUTER JOIN "PUB"."DAT-DATA" fn on "PUB"."NAME"."NAME-ID" = fn."DAT-SRC-ID" and 11 = fn."FLD-FIELD-ID"
When I run the query I get:
ORBC Progress OpenEdge Wire Protocol driver][OPENEDGE]Syntax error SQL statement at or about "is null then "PUB"."NAME"."FIRST-" (10713)
If I do a select * I see everything. It just doesn't like the null part. I can also change the when is null to when 'bob' and it works.
Is there something different I need to do to use a null value in a progress db query?
The shorthand variation of the case statement (case expression when value then result ...) is a shorthand for a series of equality conditions between the expression and the given values. null, however, is not a value - it's the lack thereof, and must be evaluated explicitly with the is operator, as you tried to do. In order to do this properly, however, you need to use a slightly longer variation of the case syntax - case when condition then result ...:
SELECT
"PUB"."NAME"."LAST-NAME" as LastName,
CASE WHEN fn."SPECIAL-CHAR" IS NULL THEN "PUB"."NAME"."FIRST-NAME"
ELSE fn."SPECIAL-CHAR"
END as FirstName
FROM "PUB"."NAME"
LEFT OUTER JOIN "PUB"."DAT-DATA" fn on "PUB"."NAME"."NAME-ID" = fn."DAT-SRC-ID" and 11 = fn."FLD-FIELD-ID"
Instead of CASE you can use IFNULL function in Progress 4GL.
SELECT
"PUB"."NAME"."LAST-NAME" as LastName,
IFNULL(fn."SPECIAL-CHAR", "PUB"."NAME"."FIRST-NAME") as FirstName
FROM "PUB"."NAME"
LEFT OUTER JOIN "PUB"."DAT-DATA" fn on "PUB"."NAME"."NAME-ID" = fn."DAT-SRC-ID" and 11 = fn."FLD-FIELD-ID"
I am having trouble with some sql. When I run the following query:
Select * from teleapp;
I get TONS of results. Resulst which include a column (called cashwithappyn) that has TONS of empty or null data cells. (They look empty and don't say null)
The column info is:
ColumnName ID Null? Data Type Histogram Num Distinct Num Nulls Density
CASHWITHAPPYN 54 Y VARCHAR2(1 Byte) Frequency 2 56895 0
When I try to run the following query:
Select * from teleapp where cashwithappyn = null;
or
Select * from teleapp where cashwithappyn = '';
or
Select * from teleapp where cashwithappyn not like '';
or
Select * from teleapp where cashwithappyn not in ('Y','N');
or ANY type of combination, I cannot seem to get all of the rows with nothing in cashwithappyn.
Any ideas? Please help, this is the last part of a project that I was assigned to do and I just need to figure this out.
Thanks.
Maybe the column contains blanks. In that case you can do
WHERE TRIM(CASHWITHAPYYN) IS NULL
TRIM removes all blanks before and after and if nothing is left anymore the value becomes NULL
e.g.
TRIM(' ') IS NULL -- one blank removed = true
TRIM(NULL) IS NULL -- true
Also NULL cannot be compared with = NULL but must be phrased IS NULL. NULL is not a value as such and that is why the comparison never works.
You need to use IS NULL
Select * from teleapp where cashwithappyn is null;
Logical test expressions (=, Not In, Like etc) with null result in a false so all of the following result in false
1 = NULL
1 <> NULL
NULL = NULL
NULL <> NULL
NULL NOT IN ('a','b')
NULL Not Like NULL
Additionally in oracle the zero length string is null so NOT LIKE '' will never return any rows
You'll need to use either is null, is not null or Coalesce
A co-worker and I did a bunch of research, here's what we came up with that will work. Any ideas why this works but not the others?
Select * from teleapp where nvl(cashwithappyn,'U') = 'U';