I am currently working with a MS SQL database on Windows 2012 Server
I need to query only 1 column from a table that I only have access to read, not make any kind of changes.
Problem is that the name of the column is "Value"
My code is this:
SELECT 'Value' FROM table
If I add
`ORDER BY 'Value'`
The issue is that the query is returning an empty list of results.
Things I've tried already
I tried replacing ' with `"' but this didn't work either.
I also tried writing SELECT * instead of SELECT VALUE
Using the table name in the SELECT or ORDER clauses again didn't help
You are claiming that this query:
SELECT 'Value'
FROM table
ORDER BY 'Value'
Is returning no rows. That's not quite correct. It is returning an error because SQL Server does not allow constant expressions as keys for ORDER BY (or GROUP BY for that matter).
Do not use single quotes. In this case:
SELECT 'Value' as val
FROM table
ORDER BY val;
Or, if value is a column in the table:
SELECT t.Value
FROM table t
ORDER BY t.Value;
Value is not a reserved word in SQL Server, but if it were, you could escape it:
SELECT t.[Value]
FROM table t
ORDER BY t.[Value];
it looks like your table has null values. and because of the order by all null values come first.
try to add filter like this
select Value FROM table
where Value is not null and Value <> ''
order by Value
Related
I am working on a query that will check the temp table if there is a record that do not exist on the main table. My query looks like this
SELECT * FROM [Telemarketing].[dbo].[PDCampaignBatch_temp]
WHERE [StartDateTime] NOT IN (SELECT [StartDateTime] FROM [Telemarketing].[dbo].PDCampaignBatch GROUP BY [StartDateTime])
but the problem is it does not display this row
even if that data does not exist in my main table. What seems to be the problem?
NOT IN has strange semantics. If any values in the subquery are NULL, then the query returns no rows at all. For this reason, I strongly recommend using NOT EXISTS instead:
SELECT t.*
FROM [Telemarketing].[dbo].[PDCampaignBatch_temp] t
WHERE NOT EXISTS (SELECT 1
FROM [Telemarketing].[dbo].PDCampaignBatch cb
WHERE t.StartDateTime = cb.StartDateTime
);
If the set is evaluated by the SQL NOT IN condition contains any values that are null, then the outer query here will return an empty set, even if there are many [StartDateTime]s that match [StartDateTime]s in the PDCampaignBatch table.
To avoid such issue,
SELECT *
FROM [Telemarketing].[dbo].[PDCampaignBatch_temp]
WHERE [StartDateTime] NOT IN (
SELECT DISTINCT [StartDateTime]
FROM [Telemarketing].[dbo].PDCampaignBatch
WHERE [StartDateTime] IS NOT NULL
);
Let's say PDCampaignBatch_temp and PDCampaignBatch happen to have the same structure (same columns in the same order) and you're tasked with getting the set of all rows in PDCampaignBatch_temp that aren't in PDCampaignBatch. The most effective way to do that is to make use of the EXCEPT operator, which will deal with NULL in the expected way as well:
SELECT * FROM [Telemarketing].[dbo].[PDCampaignBatch_temp]
EXCEPT
SELECT * FROM [Telemarketing].[dbo].[PDCampaignBatch]
In production code that is not a one-off, don't use SELECT *, write out the column names instead.
Most likely your issue is with the datetime. You may be only displaying a certain degree of percision like the year/month/date. The data may be stored as year/month/date/hour/minute/second/milisecond. If so you have to match down the the most granluar measurement of the data. If one field is a date and the other is a date time they also will likely never match up. Thus you always get no responses.
I get the following error message
"Your query does not include the specified expression 'SampleCode' as part of an aggregate function."
I've looked into aggregate functions and have tried various ways to GROUP BY using the individual data fields that make up the code but I can't seem to get anything to work.
'SampleCode' is a concatenated query field (query name: datqry_SampleNumber) that is based on data from 3 different tables to create a unique value as follows...
SampleCode: IIf([tbl_Carcass.SampleNumber]="-999","-999",
"NPT-" & [tbl_SurveyInfo.SurveyYear*] & "-" &
[datqry_TransectData.Project_Code] & "-" & [tbl_Carcass.SampleNumber])
for SampleNumber values > 0001 (-999 is a placeholder indicating no SampleNumber assigned). Note, SurveyYear* is a calculated field based on the SurveyDate data field.
So, since SampleCode needs to be unique to each sample, I am trying to build a duplicate query, based on the aforementioned query, to identify duplicate SampleCodes so they can be relabeled and archived w/ a unique qualifier. The criteria for the duplicate query operation is as follows
In (SELECT [SampleCode] FROM [datqry_SampleNumber] As Tmp
GROUP BY [SampleCode] HAVING Count(*)>1 )
Any ideas on how to tackle this problem? Thank you in advance for your help and suggestions.
This looks like it might be a limitation of the JET engine used by Access to interpret its SQL.
It appears to be having trouble working with the subquery because it contains an aggregation of a calculated field (SampleCode in your case).
Try saving this as a separate query called, e.g. qryDuplicates:
SELECT [SampleCode] FROM [datqry_SampleNumber]
GROUP BY [SampleCode] HAVING Count(*)>1;
Then what you are trying to do will work as expected:
SELECT * from someTable WHERE someField IN (
SELECT * FROM qryDuplicates
);
TECHNICAL NOTE: I've tested it out and it is indeed specific to the fact that SampleCode is a calculated field. Doing exactly the same kind of grouped subquery works as expected when the field in question is not calculated.
With this test database this query works:
SELECT * FROM Table2 WHERE Field3 IN (
SELECT Field1 FROM datqry_SampleNumber
GROUP BY Field1 HAVING COUNT(*) > 1
);
And this doesn't
SELECT * FROM Table2 WHERE Field3 IN (
SELECT SampleCode FROM datqry_SampleNumber
GROUP BY SampleCode HAVING COUNT(*) > 1
);
I am retreiving values from a Table which in turn i am comparing with values from another table using the SQL keywords 'EXCEPT'
My query looks something like follows
SELECT DISTINCT TDC_TREE_FAMILY_CLASSIFICATION AS DPC_Level1,
TDC_TREE_CLASSIFICATION AS DPC_Level2,
TDC_TREE_SUB_CLASSIFICATION AS DPC_Level3
FROM TD_DATA_PACK_CONTENTS
EXCEPT
SELECT DPC_Level1,DPC_Level2,DPC_Level3 FROM DATA_PACK_CATEGORIES
ORDER BY DPC_Level1
Now this query works fine . What i want to do is save the results in a single string variable.
So I declare 3 temps variables to save the values of DPC_Level1,Lvl2,Lvl3 and then i can join them into a single string variable.
So i modify my Query like this.
SELECT DISTINCT #m_DPC_Level11=TDC_TREE_FAMILY_CLASSIFICATION AS DPC_Level1
,#m_DPC_Level2=TDC_TREE_CLASSIFICATION AS DPC_Level2,
,#m_DPC_Level13=TDC_TREE_SUB_CLASSIFICATION AS DPC_Level3
FROM TD_DATA_PACK_CONTENTS
EXCEPT
SELECT DPC_Level1,DPC_Level2,DPC_Level3 FROM DATA_PACK_CATEGORIES
ORDER BY DPC_Level1
But this throws the error
'A SELECT statement that assigns a value to a variable must not be
combined with data-retrieval operations'
. How i resolve this issue. I am using SQL Server 2008
I would go for a subquery
select #m_DPC_LEvel11 = DPC_Level1,
#m_DPC_Level2 = DPC_Level2,
#m_DPC_Level13 = DPC_Level3,
FROM
(SELECT DISTINCT TDC_TREE_FAMILY_CLASSIFICATION AS DPC_Level1,
TDC_TREE_CLASSIFICATION AS DPC_Level2,
TDC_TREE_SUB_CLASSIFICATION AS DPC_Level3
FROM TD_DATA_PACK_CONTENTS
EXCEPT
SELECT DPC_Level1,DPC_Level2,DPC_Level3 FROM DATA_PACK_CATEGORIES
ORDER BY DPC_Level1) s
Let's say that we have a table named Data with Id and Weather columns. Other columns in that table are not important to this problem. The Weather column can be null.
I want to display all rows where Weather fits a condition, but if there is a null value in weather then display null value.
My SQL so far:
SELECT *
FROM Data d
WHERE (d.Weather LIKE '%'+COALESCE(NULLIF('',''),'sunny')+'%' OR d.Weather IS NULL)
My results are wrong, because that statement also shows values where Weather is null if condition is not correct (let's say that users mistyped wrong).
I found similar topic, but there I do not find appropriate answer.
SQL WHERE clause not returning rows when field has NULL value
Please help me out.
Your query is correct for the general task of treating NULLs as a match. If you wish to suppress NULLs when there are no other results, you can add an AND EXISTS ... condition to your query, like this:
SELECT *
FROM Data d
WHERE d.Weather LIKE '%'+COALESCE(NULLIF('',''),'sunny')+'%'
OR (d.Weather IS NULL AND EXISTS (SELECT * FROM Data dd WHERE dd.Weather LIKE '%'+COALESCE(NULLIF('',''),'sunny')+'%'))
The additional condition ensures that NULLs are treated as matches only if other matching records exist.
You can also use a common table expression to avoid duplicating the query, like this:
WITH cte (id, weather) AS
(
SELECT *
FROM Data d
WHERE d.Weather LIKE '%'+COALESCE(NULLIF('',''),'sunny')+'%'
)
SELECT * FROM cte
UNION ALL
SELECT * FROM Data WHERE weather is NULL AND EXISTS (SELECT * FROM cte)
statement show also values where Wether is null if condition is not correct (let say that users typed wrong sunny).
This suggests that the constant 'sunny' is coming from end-user's input. If that is the case, you need to parameterize your query to avoid SQL injection attacks.
Suppose I have a table with following records
value text
company/about about Us
company company
company/contactus company contact
I have a very simple query in sql server as below. I am having problem with the 'or' condition. In below query, I am trying to find text for value 'company/about'. If it is not found, then only I want to run the other side of 'or'. The below query returns two records as below
value text
company/about about Us
company company
Query
select
*
from
tbl
where
value='company/about' or
value=substring('company/about',0,charindex('/','company/about'))
How can I modify the query so the result set looks like
value text
company/about about Us
A bit roundabout, but you can check for the existence of results from the first where clause:
select
*
from
tbl
where
value='company/about' or
(
not exists (select * from tbl where value='company/about')
and
value=substring('company/about',0,charindex('/','company/about'))
)
Since your second condition can be re-written as value = 'company' this would work (at least for the data and query you've presented):
select top(1) [value], [text]
from dbo.MyTable
where value in ('company/about', 'company')
order by len(value) desc
The TOP() ignores the second row if both are found, and the ORDER BY ensures that the first row is always the one with 'company/about', if it exists.