requestId Consultantid statusid
1 2 10
2 2 10
3 2 10
I want to check if every row has a statusid of 10.
if (every row has a statusid of 10) then
-----do this
endif;
I'm a bit rusty on PL-SQL, but something like this would work in T-SQL:
if not exists (select * from your_table where statusid <> 10) then
-- whatever
end
Edit:
Ok, apparantly in PL-SQL, you need to do something like this:
DECLARE
notallten INTEGER;
BEGIN
SELECT COUNT(*) INTO notallten
FROM your_table
WHERE statusid <> 10
AND ROWNUM = 1;
IF notallten = 0 THEN
-- Do something
END IF;
END;
I don't have an Oracle server to test on though.
declare
v_exists_status_10 number(1);
...
begin
...
-- v_exists_status_10 = 0 if no such row exist, 1 if at least one does
select count(*)
into v_exists_status_10
from dual
where exists
(select * from your_table where statusid <> 10);
if v_exists_status_10 > 0 then
...
Note that you could also do a dumb COUNT() into a variable, but it could be massively inefficient compared to EXISTS. With a COUNT() you'd have to scan all the records, whereas with an EXISTS as soon as it hits a statusid = 10 it can stop scanning.
Simpler solution, that accounts for NULLs in statusid:
for r in (
select 1 dummy
from your_table
where (statusid != 10 or statusid is null)
and rownum = 1) loop
-----do this
end loop;
Related
I have a table which looks like this:
ID
money_earned
days_since_start
1
1000
1
1
2000
2
1
null
3
1
3000
4
1
2000
5
2
1000
1
2
null
2
2
100
3
I want that rows, without a value in money_earned (which means that the money_earned column was empty that day) - will and fill the money_earned with last known value, so it to look like this:
ID
money_earned
days_since_start
1
1000
1
1
2000
2
1
2000
3
1
3000
4
1
2000
5
2
1000
1
2
1000
2
2
100
3
I have tried to look up for something like that, but postgresql doesn't support ignore nulls in lag window function :(
thank you!
The LOG() function would be suitable for this purpose, but in your
case you need to get first not null previous element. What the LOG()
function can't handle.
I suggest creating your own function that would return the first non-null value of the previous element.
CREATE OR REPLACE FUNCTION log_not_null(row_num int, dafult text = '1001') RETURNS text LANGUAGE plpgsql AS $$
DECLARE
result text;
index int;
BEGIN
if row_num > 0 then
index := row_num - 1;
else
return dafult;
end if;
result := (select money_earned from my_table offset index limit 1);
if result is null then
return log_not_null(index);
end if;
return result;
END
$$;
select id, log_not_null((row_number() over ())::int) as money_earned, days_since_start from my_table;
Note:
If the previous value is null, then the function is called recursively until it reaches the top element, and if the topmost element is also null, then the function will return the value from the dafult variable.
Demo in sqldaddy.io
You can do this (warning, untested! 😎):
UPDATE yourtable t1
SET money_earned = t3.money_earned
FROM yourtable
LEFT JOIN (SELECT
ID,
MAX(days_since_start) m
FROM yourtable
WHERE ID=t1.ID AND days_since_start<t1.ID) t2 ON t2.ID=i1.ID
INNER JOIN yourtable t3 ON t3.ID=t1.ID and t3.days_since_start = t2.days_since_start
WHERE t1.money_earned is null
How do I write an effiecient query to determine if 1 or more values are 10+ in a column. I am aware that I can count the values but this will scan all the records. Here is what I have so far:
SELECT COUNT(*) FROM MyTable WHERE [state] = 12 AND age > 110
I want this query to stop when it find the first person over 110 not scan the entire table. Is this possible?
You can use a subquery to return 1 or no row using this query:
SELECT TOP 1 1 as row_exists
FROM MyTable
WHERE [state] = 12 AND age > 110;
You can use a subquery to return 1 or NULL using this as a subquery:
SELECT (SELECT TOP 1 1 FROM MyTable WHERE [state] = 12 AND age > 110
) as row_exists;
You can put this into T-SQL using:
IF (EXISTS (SELECT 1 FROM MyTable WHERE [state] = 12 AND age > 110))
BEGIN
. . .
END;
TOP is not needed in an EXISTS subquery.
So you wish to have the scalar Boolean result? The exists will quite once any row matches the condition
DECLARE #Result bit =
(SELECT CASE WHEN EXISTS(SELECT * FROM MyTable WHERE [state] = 12 AND age > 110) THEN 1 ELSE 0 END)
I am not sure wether the it is helpful for you, but you can try to test:
For example you can want to determine the result set row count is 100.
you can use top 100 base your statement.
if the orignal result lines is more than 100, then ##ROWCOUNT will be true.
SELECT TOP 100 FROM MyTable WHERE [state] = 12 AND age > 110
IF ##ROWCOUNT=100
PRINT 'True'
ELSE
PRINT 'Flase'
This question already has an answer here:
Oracle Select Statement in IF condition
(1 answer)
Closed 9 years ago.
I want to put in the if condition select query:
IF ( 10 in (select id from ids where ..) ) then ...
/* */
END IF;
How can implement that in the correct syntax ?
If you're using SQL Server then the obvious way is to use EXISTS, e.g.
if exists(select id from ids where id = 10)
begin
print 'it exists'
end
An alternative is to use the equivalent keywords SOME or ANY
if 10 = some(select id from ids)
begin
print 'it exists'
end
This may help - all examples are equiv to IF in Oracle SQL.
CASE Expressions:
SELECT deptno, empno, ename
, (CASE WHEN deptno = 10 THEN 1 ELSE 0 END) check_dept
FROM scott.emp
ORDER BY 1
/
DECODE() function:
SELECT deptno, empno, ename, DECODE(deptno, 10, 1, 0) check_dept
FROM scott.emp
ORDER BY 1
/
Your example - CASE..:
select id, (CASE WHEN id = 10 THEN 1 ELSE 0 END) AS check_id from ids where...
/
for ( --
-- The following select statement returns
-- records only, if there are any whose
-- ID = 10.
-- The rownum = 1 condition makes sure that
-- at most one record is returned.
--
select null
from ids
where id = 10 and
rownum = 1) loop
/*
Do something if at least on record is selected
by the select statement.
*/
end loop;
While this "solution" should do what you want, I don't necessarily recommend to do it like so because it might not be intrinsically clear for a later maintainer of the code what the purpose if this for ... loop exactly was. You might want to consider using a variable into which you select the count of the records with id=10 and do your thing based upon cnt>0.
I have a table something like
EMPLOYEE_ID DTL_ID COLUMN_A COLUMN_B
---------------------------
JOHN 0 1 1
JOHN 1 3 1
LINN 0 1 12
SMITH 0 9 1
SMITH 1 11 12
It means for each person there will be one or more records with different DTL_ID's value (0, 1, 2 .. etc).
Now I'd like to create a T-SQL statement to retrieve the records with EMPLOYEE_ID and DTL_ID.
If the specified DTL_ID is NOT found, the record with DTL_ID=0 will be returned.
I know that I can achieve this in various ways such as checking if a row exists via EXISTS or COUNT(*) first and then retrieve the row.
However, I'd like to know other possible ways because this retrieval statement is very common in my application and my table have hundred thousand of rows.
In the above approach, I've had to retrieve twice even if the record with the DTL_ID specified exists, and I want to avoid this.
Like this:
SELECT *
FROM table
WHERE EMPLOYEE_ID = ?? AND DTL_ID = ??
UNION
SELECT *
FROM table
WHERE EMPLOYEE_ID = ?? AND DTL_ID = 0
AND NOT EXISTS (SELECT *
FROM table
WHERE EMPLOYEE_ID = ?? AND DTL_ID = ??)
You will of course have to fill in the ?? with the proper number.
If DTL_ID is always 0 or positive:
SELECT TOP 1 * FROM table
where EmployeeID = #EmployeeID and DTL_ID in (#DTL_ID,0)
order by DTL_ID desc
If you're working across multiple employees in a single query, etc, then you might want to use ROW_NUMBER() if your version of SQL supports it.
Use ISNULL(DTL_ID, 0) in your final SELECT query
SELECT E1.EMPLOYEE_ID, ISNULL(E2.DTL_ID, 0), E1.COLUMN_A, E1.COLUMN_B EMPLIYEES AS E1
LEFT JOIN EMPLIYEES AS E2
ON E1.EMPLOYEE_ID = E2.EMPLOYEE_ID AND E2.DTL_ID = 42
You can use top and union, e.g.:
declare #t table(id int, value int, c char)
insert #t values (1,0,'a'), (1,1,'b'), (1,2,'c')
declare #id int = 1;
declare #value int = 2;
select top(1) *
from
(
select *
from #t t
where t.value = #value and t.id = #id
union all
select *
from #t t
where t.value = 0
)a
order by a.value desc
If #value = 2 than query returns 1 2 c. If #value = 3 than query returns 1 0 a.
SELECT MAX(DTL_ID) ...
WHERE DTL_ID IN (#DTL_ID, 0)
Basically, what syntex would allow me to achieve the title statement?
If (select statement 1) returns 0 rows THEN (select statement 2) else (select statement 3)
So that the sql returns results from either statement 2 or 3
I've looked for a way to do this but nothing I've found so far seems to exactly address the if requirements.
IF EXISTS (SELECT field FROM table)
BEGIN
SELECT field FROM table2
END
ELSE
BEGIN
SELECT field FROM table3
END
Here you go...
IF ((select count(*) from table1)= 0)
BEGIN
Select * from table2
END
ELSE
BEGIN
SELECT * from table3
END
Sorry for the lack of feedback. Someone else in the office took an interest and came up with this:
select * from (
select *
, (SELECT Count(*)
FROM users
WHERE version_replace = 59 AND moderated = 1) AS Counter
FROM users WHERE version_replace = 59 AND moderated in (0,1)
) AS y
where Counter = 0 and Moderated = 0
or Counter > 0 and Moderated = 1
ORDER By ID DESC
Which does what I need.