I want to be able to check if we have a column and if not, then we just want to add an empty column,
IF Users.[parties] = '' OR NULL
BEGIN
SELECT [parties]
FROM Users
UNION
SELECT 'Empty'
END
The Users.[parties], we check to see if we have a column but if we don't, it will result in a crash, in the case for this event I thought it would be best just to add an empty column with the name of Empty but I can't get the code to work above.
If we do have columns, the results will be something like...
ColumnsName ColumnAge
data 33
data 22
But when there isn't a column, it crashes and ideally I would like it to just have an empty column like this,
EmptyColumn
The code below checks whether a column exists in the table, in our case the name of the column is columnName and the name of the table is tableName.
IF COL_LENGTH('schemaName.tableName', 'columnName') IS NOT NULL
BEGIN
-- Column exists
SELECT [parties] FROM Users
END
ELSE
BEGIN
-- Column does not exists
SELECT 'Empty'[parties]
END
I think you just want
IF EXISTS(
SELECT 1
FROM Sys.Columns
WHERE Name = N'parties'
AND
Object_ID = Object_ID(N'SchemaName.Users')
)
BEGIN
SELECT parties
FROM Users;
END
ELSE
BEGIN
SELECT 'EmptyColumn' EmptyColumn -- or NULL EmptyColumn
FROM Users;
END
I'll try with this: (I'm not sure it works)
select case when ROW_NUMBER() OVER (ORDER BY (SELECT NULL)) =0 --count rows
then 'empty' -- if 0 output empty
else parties end as parties --else ouputs the result
from your_table
This is a more 'standard' approach
CREATE VIEW user_filled as
SELECT [parties]
FROM Users
UNION
SELECT 'EMPTY'
and when you query it (if needed -> on count(*))
select count(*)
from user_filled
where parties <> 'EMPTY'
on join
select *
from user_filled join other_table
on (user_filled <> 'EMPTY and userfilled.key= other_table.key)
NOTE: put the clause into the ON so it's filtered out BEFORE the join is made
Related
I want to create a table with fetch the data from source table.
I can do it using alter and update function but I don't want to do it that way.
I have to create two columns and use 1 column(c1) in other as case statement in second(c2) column.
insert into table t
(select
a,b, case when d>f then 1 else 0 end as c1,
case when c1=1 then "yes" else null end as c2,
from base_temp
where a>b
)
If the question is on how to create a table and populate it with the results of some SELECT statement, then look at the CREATE TABLE as-result-table syntax.
You may use AS (full-select) WITH DATA syntax to create a new table with metadata based on the query provided and insert the result of this query into this table at the same time.
If the question is on how to use column aliases in expressions, then refer to the Expressions refer to column aliases topic.
You must have the SQL_COMPAT global variable set to the 'NPS' value in your session to make it work.
You may set it with the SET SQL_COMPAT = 'NPS' statement before running the corresponding SELECT statement.
SET SQL_COMPAT='NPS';
SELECT
TABSCHEMA, TABNAME
, CASE WHEN COLCOUNT > 20 THEN 1 ELSE 0 END AS C1
, CASE WHEN C1 = 1 THEN 'YES' ELSE NULL END AS C2
FROM SYSCAT.TABLES
FETCH FIRST 5 ROWS ONLY;
If you can't or don't want to set this variable, you may use sub-select to achieve the same:
SELECT
TABSCHEMA, TABNAME
, C1
, CASE WHEN C1 = 1 THEN 'YES' ELSE NULL END AS C2
FROM
(
SELECT
TABSCHEMA, TABNAME
, CASE WHEN COLCOUNT > 20 THEN 1 ELSE 0 END AS C1
FROM SYSCAT.TABLES
FETCH FIRST 5 ROWS ONLY
);
I want to update a column. When the value is not in the list or in table or doesn't match, it will return "Not Account Related" and when the value is in the list, the row will become blank. So this is my query.
SELECT
CASE Project_Names
WHEN "List_Value_Name".[LK_ProjectNames] = "Project_Names".[1]
THEN ''
ELSE "Not Account Related"
END
FROM
[master].[dbo].[1]
Table is LK_ProjectNames with columns List_Value_Name & table 1 with column Project_Names.
If value in table 1 column Project_Names got in the table LK_ProjectNames column List_Value_Name, it will return blank. if not it will return Not Account Related
If you are storing project name in table1 in one row one project basis.
SELECT *,
CASE WHEN EXISTS(SELECT 1 FROM LK_ProjectNames l WHERE LTRIM(RTRIM(t.Project_Names)) =LTRIM(RTRIM(l.List_Value_Name)) ) THEN '' ELSE 'Not Account Related' END as RESULT
FROM table1 t
If you are storing project names as comma seperated in table1 .
SELECT *,
CASE WHEN EXISTS(SELECT 1 FROM LK_ProjectNames l WHERE LTRIM(RTRIM(t.Project_Names)) like '%'+LTRIM(RTRIM(l.List_Value_Name))+'%' ) THEN '' ELSE 'Not Account Related' END as RESULT
FROM table1 t
How can I change column text Not Exists when it is empty or null ?
My query :
Select TOP 1 ISNULL(NULLIF(DR.Name,''),'Not Exists') as Name,
DR.Name as Name ,Coalesce(NullIf(rtrim(DR.Name),''),'Not Exist') as Name,
Name = case when DR.Name is null then 'Not Exists'
when DR.Name='' then 'Not Exists' else DR.Name end
from Transfer TR
join Driver DR on DR.OID=TR.DriverID
WHERE TR.TruckID=51 AND TR.Statues<>7 and TR.DateScheduled<GETDATE()
AND TR.DateScheduled>=DATEADD(DAY,-7,GETDATE()) ORDER BY TR.OID DESC
Result :
If you just need a single column, then you can use a sub-select, this way when no rows are returned by the query you will still get not exists:
SELECT Name = ISNULL(( SELECT TOP 1 NULLIF(DR.Name,'')
FROM Transfer AS TR
INNER JOIN Driver AS DR
ON DR.OID = TR.DriverID
WHERE TR.TruckID = 51
AND TR.Statues <> 7
AND TR.DateScheduled < GETDATE()
AND TR.DateScheduled >= DATEADD(DAY, -7, GETDATE())
ORDER BY TR.OID DESC), 'Not Exists');
If you need multiple columns then you could union your Not Exists record to the bottom of the query, place all this inside a subquery then select the top 1 again, ensuring that your actual value takes precedence (by adding the column SortOrder):
SELECT TOP 1 Name, SomeOtherColumn
FROM ( SELECT TOP 1
Name = NULLIF(DR.Name,''),
SomeOtherColumn,
SortOrder = 0
FROM Transfer AS TR
INNER JOIN Driver AS DR
ON DR.OID = TR.DriverID
WHERE TR.TruckID = 51
AND TR.Statues <> 7
AND TR.DateScheduled < GETDATE()
AND TR.DateScheduled >= DATEADD(DAY, -7, GETDATE())
ORDER BY TR.OID DESC
UNION ALL
SELECT 'Not Exists', NULL, 1
) AS t
ORDER BY SortOrder;
I'm not entirely sure I understand your question, but if you are trying to catch nulls and empty strings "in one go", try this:
select TOP 1
case when length(trim(coalesce(DR.Name, ''))) = 0 then
'Not Exists'
else
DR.Name
as Name
....
The coalesce catches the NULLs and sets a replacement value. The trim gets rid of any padding and the length checks if what is left is an empty string --> so this covers nulls, padded- and non-padded trivial strings.
Assuming the value has regular spaces, the following would keep your approach:
Select TOP 1 ISNULL(NULLIF(ltrim(rtrim((DR.Name))), ''), 'Not Exists') as Name,
I would probably go with the more explicit:
select top 1 (case when ltrim(rtrim((DR.Name)) = '' or DR.Name is null then 'Not Exists'
else DR.Name end) as Name
Unless you also wanted the spaces removed from Name in the output.
If you have other characters, then you can use ASCII() to find them. Something like:
select ASCII(LEFT(DR.Name, 1))
. . .
where LEFT(DR.Name, 1) NOT LIKE '[a-zA-Z0-9 ]' -- you can expand this list of allowed characters
It seems to me you are not actually looking for a way to replace an empty string with 'Not Exists', but an empty result set.
In other words: It looks like you are looking for a way to show 'Not Exists' in case your query returns no rows. If it is this what you are looking for, then first "add" a 'Not Exists' record to your result set and then show the best row, i.e. the desired row in case such a row exists, else your 'Not Exists' row.
select top 1 name
from
(
select name, tr.oid
from transfer tr
join driver dr on dr.oid=tr.driverid
where tr.truckid=51 and tr.statues<>7 and tr.datescheduled<getdate()
and tr.datescheduled>=dateadd(day,-7,getdate())
union all
select 'Not Exists', -1
)
order by oid desc;
I chose -1 for the dummy OID. It must be a value smaller than any real OID. So if you have negative values, make that value even smaller.
I have a table with several rows, and several columns. It looks like this:
Name Description
X PASS
X PASS
X FAIL
I want it to return only one row. If all of them are PASS, return PASS.
If one or more of them are FAIL, then return FAIL.
What's the best way to go about achieving this in SQL Server 2008?
EDIT: The values in the name column will always be the same.
Depending on the database indexes, and assuming you want one row returned per unique name, I would look at the performance of
select
name,
min([description]) as description
from
tableA
group by
name
compared to the other solutions
SELECT TOP 1 CASE Description WHEN 'FAIL' THEN 'FAIL' ELSE 'PASS' END
FROM DaTable
ORDER BY Description
OP: Is it possible that the table is empty? In that case this query won't return any rows, obviously.
EDIT
According to aquinas's comment I created a modified query without ordering:
SELECT CASE COUNT(Description) WHEN 0 THEN 'FAIL' ELSE 'PASS' END
FROM DaTable
WHERE Description = 'FAIL'
This query will return PASS if DaTable is empty.
This is the simplest solution you will find:
SELECT MIN(Description) FROM tbl
If there's at least one FAIL, then our result column will contain FAIL, otherwise, it will contain PASS.
You can use EXISTS to get the existance of a row containing "FAIL".
You could also try something like:
SELECT TOP 1 COALESCE(tFail.Description,t.Description)
FROM myTable AS t
LEFT JOIN myTable AS tFail ON tFail.Name = t.Name AND tFail.Description = 'FAIL'
WHERE t.Name = 'x'
Here is the query:
--DROP TABLE result
CREATE TABLE result(Name varchar(10),Description varchar(20))
--select * from result
INSERT INTO result
VALUES('X','PASS'),('X','PASS'),('X','FAIL')
;WITH CTE(descp,cnt) as (SELECT [description],COUNT(*) as cnt FROM result group by [description])
SELECT CASE WHEN COUNT(*) > 1 then 'FAIL' when COUNT(*)=1 then MAX(descp) else 'PASS' END FROM CTE
A)
select decode(count(*), 0, 'N', 'Y') rec_exists
from (select 'X'
from dual
where exists (select 'X'
from sales
where sales_type = 'Accessories'));
B)
select decode(count(*), 0, 'N', 'Y') rec_exists
from (select 'X'
from sales
where sales_type = 'Accessories');
C) Something else (specify)
EDIT: It was hard to pick the "correct" answer, as the best approach depends on what you want to do after checking if the value exists, as pointed out by APC. I ended up picking the answer by RedFilter, since I had originally envisioned this check as a function by itself.
select case
when exists (select 1
from sales
where sales_type = 'Accessories')
then 'Y'
else 'N'
end as rec_exists
from dual;
What is the underlying logic you want to implement? If, for instance, you want to test for the existence of a record to determine to insert or update then a better choice would be to use MERGE instead.
If you expect the record to exist most of the time, this is probably the most efficient way of doing things (although the CASE WHEN EXISTS solution is likely to be just as efficient):
begin
select null into dummy
from sales
where sales_type = 'Accessories'
and rownum = 1;
-- do things here when record exists
....
exception
when no_data_found then
-- do things here when record doesn't exists
.....
end;
You only need the ROWNUM line if SALES_TYPE is not unique. There's no point in doing a count when all you want to know is whether at least one record exists.
select count(1) into existence
from sales where sales_type = 'Accessories' and rownum=1;
Oracle plan says that it costs 1 if seles_type column is indexed.
here you can check only y , n
if we need to select a name as well that whether this name exists or not.
select name , decode(count(name),0, 'N', 'Y')
from table
group by name;
Here when it is Y only then it will return output otherwise it will give null always. Whts ths way to get the records not existing with N like in output we will get Name , N. When name is not existing in table
Simply get a count of the record(s) you're looking for. If count > 0 then record(s) exist.
DECLARE
rec_count NUMBER := 0;
BEGIN
select count(*)
into rec_count
from EMPLOYEETABLE
WHERE employee_id = inEMPLOYEE_ID
AND department_nbr = inDEPARTMENT_NBR;
if rec_count > 0 then
{UPDATE EMPLOYEETABLE}
else
{INSERT INTO EMPLOYEETABLE}
end if;
END;
select decode(count(*), 0, 'N', 'Y') rec_exists
from sales
where sales_type = 'Accessories';
select NVL ((select 'Y' from dual where exists
(select 1 from sales where sales_type = 'Accessories')),'N') as rec_exists
from dual
1.Dual table will return 'Y' if record exists in sales_type table
2.Dual table will return null if no record exists in sales_type table and NVL will convert that to 'N'
The most efficient and safest way to determine if a row exists is by using a FOR-LOOP...
You won't even have a difficult time if you are looking to insert a row or do something based on the row NOT being there but, this will certainly help you if you need to determine if a row exists. See example code below for the ins and outs...
If you are only interested in knowing that 1 record exists in your potential multiple return set, than you can exit your loop after it hits it for the first time.
The loop will not be entered into at all if no record exists. You will not get any complaints from Oracle or such if the row does not exist but you are bound to find out if it does regardless. Its what I use 90% of the time (of course dependent on my needs)...
EXAMPLE:
DECLARE
v_exist varchar2(20);
BEGIN
FOR rec IN
(SELECT LOT, COMPONENT
FROM TABLE
WHERE REF_DES = (SELECT REF_DES FROM TABLE2 WHERE ORDER = '1234')
AND ORDER = '1234')
LOOP
v_exist := "IT_EXISTS"
INSERT INTO EAT_SOME_SOUP_TABLE (LOT, COMPONENT)
VALUES (rec.LOT, rec.COMPONENT);**
--Since I don't want to do this for more than one iteration (just in case there may have been more than one record returned, I will EXIT;
EXIT;
END LOOP;
IF v_exist IS NULL
THEN
--do this
END IF;
END;
--This is outside the loop right here The IF-CHECK just above will run regardless, but then you will know if your variable is null or not right!?. If there was NO records returned, it will skip the loop and just go here to the code you would have next... If (in our case above), 4 records were returned, I would exit after the first iteration due to my EXIT;... If that wasn't there, the 4 records would iterate through and do an insert on all of them. Or at least try too.
By the way, I'm not saying this is the only way you should consider doing this... You can
SELECT COUNT(*) INTO v_counter WHERE ******* etc...
Then check it like
if v_counter > 0
THEN
--code goes here
END IF;
There are more ways... Just determine it when your need arises. Keep performance in mind, and safety.
select CASE
when exists (SELECT U.USERID,U.USERNAME,U.PASSWORDHASH
FROM TBLUSERS U WHERE U.USERID =U.USERID
AND U.PASSWORDHASH=U.PASSWORDHASH)
then 'OLD PASSWORD EXISTS'
else 'OLD PASSWORD NOT EXISTS'
end as OUTPUT
from DUAL;
Another solution:
There are lot of solutions I saw in SO, which are good, count(1) or count(*) , when exists, where exists, left join, loop with no data exception..
I prefer below options, hope this is performant in large data, didn't check though :) :
Return 1 or 0 ( Can be used if you have checks with a number variable )
SELECT NVL(MIN(1),0)
FROM SALES
WHERE SALES_TYPE = 'ACCESSORIES' AND ROWNUM = 1
Return Y or N ( Can be used if you have checks with a string variable )
SELECT DECODE(MIN(1),1, 'Y', 'N')
FROM SALES
WHERE SALES_TYPE = 'ACCESSORIES' AND ROWNUM = 1
There are multiple options, Kindly do a performance test for your scenario and choose the best option.
SELECT 'Y' REC_EXISTS
FROM SALES
WHERE SALES_TYPE = 'Accessories'
The result will either be 'Y' or NULL.
Simply test against 'Y'