I have table variable and all its columns can not be null (NOT NULL definition for each):
DECLARE #SampleTable
(
,SampleColumnID nvarchar(400) NOT NULL PRIMARY KEY
,SampleColumnText nvarchar(max) NOT NULL
)
I have done some operation with this variable and initialize the "SampleColumnText" with some text.
Then I try to replace some part of it with text return from other function. What happens is that the function returns NULL in some cases, so I this code generates me error:
REPLACE(SampleColumnText , '{*}', #InitByFunctionText)
WHERE #InitByFunctionText is NULL this time.
So, is it normal error to be generated as I am replacing only part of the text with NULL, not the whole text?
This is expected behaviour. REPLACE:
Returns NULL if any one of the arguments is NULL.
If you want to replace it with an empty string (which is not the same as NULL), you can use COALESCE:
REPLACE(SampleColumnText , '{*}', COALESCE(#InitByFunctionText,''))
I had a similar thing recently and the following got around this issue:
REPLACE(SampleColumnText , '{*}', ISNULL(#InitByFunctionText, ''))
Related
Wanted to create the multiple parameter of function but it gives me this error:
CREATE FUNCTION failed because a column name is not specified for
column 1.
Code below:
create function dmt.Impacted(
#nameOfColumn varchar , #nameOfParam varchar)
returns table
as
return
(select
case when '['+#nameOfColumn+']' is null or len(rtrim('['+#nameOfColumn+']')) = 0
then Convert(nvarchar(2),0)
else
#nameOfParam end from employee) ;
As the error message clearly said, the column in the returned result need a name. Either give it an alias in the SELECT like
SELECT CASE
...
END a_column_name
...
or define it in the declaration of the return type as in
...
RETURNS TABLE
(a_column_name nvarchar(max)
...
As you can see in the second form you have to specify a data type. As your current code doesn't make much sense now I cannot figure out what is the right one there. You'd need to amend it.
Note, that len(rtrim('['+#nameOfColumn+']')) = 0 is never true as len(rtrim('['+#nameOfColumn+']')) is either NULL, when #nameOfColumn is NULL or at least 2 because of the added brackets.
If #nameOfColumn is supposed to be a column name you shouldn't use varchar (especially without a length specified for it) but sysname which is a special type for object names.
Either way you should define a length for #nameOfColumn and #nameOfParam as just varchar without any length means varchar(1), which is probably not what you want. And maybe instead of varchar you want nvarchar.
You may also want to look into quotename().
Define name of column in SELECT statement :
(select case when '['+#nameOfColumn+']' is null or
len(rtrim('['+#nameOfColumn+']')) = 0
then Convert(nvarchar(2),0)
else #nameOfParam
end as name_column -- define column name
from employee)
Also, your function parameter has no data length, by default it will accept only 1 character #nameOfColumn varchar , #nameOfParam varchar & rest will trim.
I am trying to copy values from a csv (with headers) into a table. I have looked at this answer which says to specify the NULL value, but it does not seem to have an effect for me. This is what I have:
CREATE TABLE stops
(
stop_id text PRIMARY KEY,
--stop_code text NULL,
stop_name text NOT NULL,
--stop_desc text NULL,
stop_lat double precision NOT NULL,
stop_lon double precision NOT NULL,
zone_id integer NULL,
stop_url text NULL,
location_type boolean NULL,
parent_station text NULL
);
\copy stops from './stops.txt' with csv header NULL AS ''
I also tried using the \N character like so:
\copy stops from './stops.txt' with csv header NULL AS '\N'
But it does not seem to have an effect.
I have also tried experimenting with a solution found here which looks like this:
\copy agency from './agency.txt' WITH (FORMAT csv header, FORCE_NULL(zone_id))
But this seems to throw a syntax error at the csv_header part.
Version is 9.6.
This is an excerpt of the csv:
stop_id,stop_name,stop_lat,stop_lon,zone_id,stop_url,location_type,parent_station
"de:07334:1714:1:1","Wörth Alte Bahnmeisterei","49.048742345982","8.26622538039577","","","","Parent1714"
"de:07334:1714:1:2","Wörth Alte Bahnmeisterei","49.0484420719247","8.26673742010779","","","","Parent1714"
"de:07334:1721:1:1","Maximiliansau Eisenbahnstraße","49.0373071007148","8.29789997731824","","","","Parent1721"
"de:07334:1721:2:2","Maximiliansau Eisenbahnstraße","49.0371363175998","8.29896897250649","","","","Parent1721"
But this seems to throw a syntax error at the csv_header part.
Put a comma after csv:
\copy agency from './agency.txt' WITH (FORMAT csv, HEADER, FORCE_NULL(zone_id,location_type))
Apparently FORCE_NULL is required for non-text columns, when using the empty string to specify NULL.
original query looks like this :
UPDATE reponse_question_finale t1, reponse_question_finale t2 SET
t1.nb_question_repondu = (9-(ISNULL(t1.valeur_question_4)+ISNULL(t1.valeur_question_6)+ISNULL(t1.valeur_question_7)+ISNULL(t1.valeur_question_9))) WHERE t1.APPLICATION = t2.APPLICATION;
I know you cannot update 2 tables in a single query so i tried this :
UPDATE reponse_question_finale t1
SET nb_question_repondu = (9-(COALESCE(t1.valeur_question_4,'')::int+COALESCE(t1.valeur_question_6,'')::int+COALESCE(t1.valeur_question_7)::int+COALESCE(t1.valeur_question_9,'')::int))
WHERE t1.APPLICATION = t1.APPLICATION;
But this query gaves me an error : invalid input syntax for integer: ""
I saw that the Postgres equivalent to MySQL is COALESCE() so i think i'm on the good way here.
I also know you cannot add varchar to varchar so i tried to cast it to integer to do that. I'm not sure if i casted it correctly with parenthesis at the good place and regarding to error maybe i cannot cast to int with coalesce.
Last thing, i can certainly do a co-related sub-select to update my two tables but i'm a little lost at this point.
The output must be an integer matching the number of questions answered to a backup survey.
Any thoughts?
Thanks.
coalesce() returns the first non-null value from the list supplied. So, if the column value is null the expression COALESCE(t1.valeur_question_4,'') returns an empty string and that's why you get the error.
But it seems you want something completely different: you want check if the column is null (or empty) and then subtract a value if it is to count the number of non-null columns.
To return 1 if a value is not null or 0 if it isn't you can use:
(nullif(valeur_question_4, '') is null)::int
nullif returns null if the first value equals the second. The IS NULL condition returns a boolean (something that MySQL doesn't have) and that can be cast to an integer (where false will be cast to 0 and true to 1)
So the whole expression should be:
nb_question_repondu = 9 - (
(nullif(t1.valeur_question_4,'') is null)::int
+ (nullif(t1.valeur_question_6,'') is null)::int
+ (nullif(t1.valeur_question_7,'') is null)::int
+ (nullif(t1.valeur_question_9,'') is null)::int
)
Another option is to unpivot the columns and do a select on them in a sub-select:
update reponse_question_finale
set nb_question_repondu = (select count(*)
from (
values
(valeur_question_4),
(valeur_question_6),
(valeur_question_7),
(valeur_question_9)
) as t(q)
where nullif(trim(q),'') is not null);
Adding more columns to be considered is quite easy then, as you just need to add a single line to the values() clause
I created a table "TEST" and i tried to input some data however i got an error. The error is ERROR: new row for relation "test" violates check constraint "test_status_check" DETAIL: Failing row contains (5 , 2015-07-21, 15:00:00, I7 , 9 , NULL, NULL).
I think it is because of the null of the status. Therefore, i tried put a null in the test table but still not working
Create table test(
clientID CHAR (20),
startDate date,
startTime time,
instructorNO CHAR(20),
centreID CHAR(20),
status CHAR(4) CHECK (status IN ('Fail','Pass')) NULL,
reason VARCHAR(400),
omitted...
)
ERROR: new row for relation "test" violates check constraint "test_status_check" DETAIL: Failing row contains (5 , 2015-07-21, 15:00:00, I7 , 9 , NULL, NULL).
EDIT: I've completely changed my mind. Your existing code is valid (and the NULL part is unnecessary).
According to the documentation,
It should be noted that a check constraint is satisfied if the check expression evaluates to true or the null value. Since most expressions will evaluate to the null value if any operand is null, they will not prevent null values in the constrained columns. To ensure that a column does not contain null values, the not-null constraint described in the next section can be used.
So, something else is messed up. See here for an example of your original code working.
I'm trying to insert a alphanumeric value in a table:
INSERT INTO solution (solution, nextsolution) VALUES
('9Na_(2)SO_(4)', NULL), ('2Ni(OH)_(3)', (SELECT id FROM solution WHERE solution='9Na_(2)SO_(4)' & nextsolution=null));
solution is of type text and nextsolution is an integer. Unfortunately postgresql doesn't allow me to do the WHERE clause. It gives me the error:
ERROR: invalid input syntax for integer: "9Na_(2)SO_(4)"
LINE 9: ...OH)_(3)', (SELECT id FROM solution WHERE solution='9Na_(2)SO...
How can I solve this?
The issue is that the statement in the where clause: '9Na_(2)SO_(4)' & nextsolution=null tries to do a bitwise and (&) operation on the string and this won't work (and probably isn't what you want anyway).
Looking at your query I think what you want is to first insert the value '9Na_(2)SO_(4)' and then the value '2Ni(OH)_(3)' with the id of the previous inserted row.
You need to do this as two statements and use a different syntax. This should do what you want:
INSERT INTO solution (solution, nextsolution) VALUES (
'9Na_(2)SO_(4)',
NULL
);
INSERT INTO solution (solution, nextsolution) VALUES (
'2Ni(OH)_(3)',
(SELECT id FROM solution WHERE solution='9Na_(2)SO_(4)' and nextsolution is null)
);
You need to use AND instead of & to join your WHERE clause - an ampersand (&) is used for bitwise operations.