I have found the following issue in SQL Server 2008 Management Studio. When I run the following script as whole I expect errors (due to a "copy and paste error"), but don't receive them.
IF OBJECT_ID('Foo') IS NOT NULL
BEGIN
DROP TABLE Foo
END
IF OBJECT_ID('Bar') IS NOT NULL
BEGIN
DROP TABLE Bar
END
CREATE TABLE Foo (
FooID int
)
Create Table Bar (
BarID int
, FooID int
)
INSERT INTO Foo
SELECT 1 UNION ALL SELECT 2
INSERT INTO Bar
SELECT 1,1 UNION ALL SELECT 2,1 UNION ALL SELECT 3,1
GO
IF OBJECT_ID('tempdb..#temp') IS NOT NULL
BEGIN
DROP TABLE #TEMP
END
GO
CREATE TABLE #TEMP (
FooID int
)
INSERT INTO #TEMP
SELECT FooID FROM Bar
GO
SELECT * FROM Foo WHERE FooID IN (SELECT FooID FROM #TEMP)
GO
SELECT * FROM Bar WHERE BarID IN (SELECT BarID FROM #TEMP)
GO
SELECT * FROM #TEMP
GO
The second last statement containing the where clause filter on "SELECT BarID FROM #TEMP" runs, but there is no BarID column in #TEMP. When running the script as a whole I receive no error and the script return all rows in Foo. However when I run the command on its own then I get the error informing me that there is no BarId in #TEMP.
Is there a reason for this? Is it my code?
Your second to last query actually is working correctly.
Other commenters please correct me, but I understand this to be a correlated subquery. Table aliasing will show what is actually going on. Your query is equivalent to this:
SELECT * FROM Bar x WHERE x.BarID IN (SELECT x.BarID FROM #TEMP)
For each row in #TEMP, the nested select is actually returning the current value of BarID from table Bar, so yes, BarID in (BarID) is true, so every row in Bar is matched, so every row is returned.
To show that you're not crazy, try
SELECT * FROM Bar WHERE BarID IN (SELECT NonExistentFieldName FROM #TEMP)
This raises the error I think you're expecting.
For some background on Neil's answer, please see the following KB article:
http://support.microsoft.com/kb/298674
The example they use (that works though it appears that it shouldn't) is quite similar to your example (though without #temp tables):
CREATE TABLE X1 (ColA INT, ColB INT)
CREATE TABLE X2 (ColC INT, ColD INT)
SELECT ColA FROM X1 WHERE ColA IN (Select ColB FROM X2)
They also show that adding the table alias (which is a good practice for many reasons, but would prevent this problem from getting past compilation) makes the query fail as you originally expected.
This is actually following the ANSI standard for column resolution, and is not going to change (unless they implement Erland's SET STRICT_CHECKS ON).
Some others who have complained about this bug (and a lot more background on why the engine has to work this way):
http://connect.microsoft.com/SQL/feedback/details/542289/
http://connect.microsoft.com/SQL/feedback/details/422252/
http://connect.microsoft.com/SQL/feedback/details/126785/
Have to agree with #BalamBalam's comment: why are you writing invalid code, and then complaining that it's mistakenly taken as valid?
Related
This question already has answers here:
sql server 2008 management studio not checking the syntax of my query
(2 answers)
Closed 1 year ago.
I have the following select:
SELECT DISTINCT pl
FROM [dbo].[VendorPriceList] h
WHERE PartNumber IN (SELECT DISTINCT PartNumber
FROM [dbo].InvoiceData
WHERE amount > 10
AND invoiceDate > DATEADD(yyyy, -1, CURRENT_TIMESTAMP)
UNION
SELECT DISTINCT PartNumber
FROM [dbo].VendorDeals)
The issue here is that the table [dbo].VendorDeals has NO column PartNumber, however no error is detected and the query works with the first part of the union.
Even more, IntelliSense also allows and recognize PartNumber. This fails only when inside a complex statement.
It is pretty obvious that if you qualify column names, the mistake will be evident.
This isn't a bug in SQL Server/the T-SQL dialect parsing, no, this is working exactly as intended. The problem, or bug, is in your T-SQL; specifically because you haven't qualified your columns. As I don't have the definition of your table, I'm going to provide sample DDL first:
CREATE TABLE dbo.Table1 (MyColumn varchar(10), OtherColumn int);
CREATE TABLE dbo.Table2 (YourColumn varchar(10) OtherColumn int);
And then an example that is similar to your query:
SELECT MyColumn
FROM dbo.Table1
WHERE MyColumn IN (SELECT MyColumn FROM dbo.Table2);
This, firstly, will parse; it is a valid query. Secondly, provided that dbo.Table2 contains at least one row, then every row from table dbo.Table1 will be returned where MyColumn has a non-NULL value. Why? Well, let's qualify the column with table's name as SQL Server would parse them:
SELECT Table1.MyColumn
FROM dbo.Table1
WHERE Table1.MyColumn IN (SELECT Table1.MyColumn FROM dbo.Table2);
Notice that the column inside the IN is also referencing Table1, not Table2. By default if a column has it's alias omitted in a subquery it will be assumed to be referencing the table(s) defined in that subquery. If, however, none of the tables in the sub query have a column by that name, then it will be assumed to reference a table where that column does exist; in this case Table1.
Let's, instead, take a different example, using the other column in the tables:
SELECT OtherColumn
FROM dbo.Table1
WHERE OtherColumn IN (SELECT OtherColumn FROM dbo.Table2);
This would be parsed as the following:
SELECT Table1.OtherColumn
FROM dbo.Table1
WHERE Table1.OtherColumn IN (SELECT Table2.OtherColumn FROM dbo.Table2);
This is because OtherColumn exists in both tables. As, in the subquery, OtherColumn isn't qualified it is assumed the column wanted is the one in the table defined in the same scope, Table2.
So what is the solution? Alias and qualify your columns:
SELECT T1.MyColumn
FROM dbo.Table1 T1
WHERE T1.MyColumn IN (SELECT T2.MyColumn FROM dbo.Table2 T2);
This will, unsurprisingly, error as Table2 has no column MyColumn.
Personally, I suggest that unless you have only one table being referenced in a query, you alias and qualify all your columns. This not only ensures that the wrong column can't be referenced (such as in a subquery) but also means that other readers know exactly what columns are being referenced. It also stops failures in the future. I have honestly lost count how many times over years I have had a process fall over due to the "ambiguous column" error, due to a table's definition being changed and a query referencing the table wasn't properly qualified by the developer...
I'm researching a dataset.
And I just wonder if there is a way to order like below in 1 query
Select * From MyTable where name ='international%' order by id
Select * From MyTable where name != 'international%' order by id
So first showing all international items, next by names who dont start with international.
My question is not about adding columns to make this work, or use multiple DB's, or a largerTSQL script to clone a DB into a new order.
I just wonder if anything after 'Where or order by' can be tricked to do this.
You can use expressions in the ORDER BY:
Select * From MyTable
order by
CASE
WHEN name like 'international%' THEN 0
ELSE 1
END,
id
(From your narrative, it also sounded like you wanted like, not =, so I changed that too)
Another way (slightly cleaner and a tiny bit faster)
-- Sample Data
DECLARE #mytable TABLE (id INT IDENTITY, [name] VARCHAR(100));
INSERT #mytable([name])
VALUES('international something' ),('ACME'),('international waffles'),('ABC Co.');
-- solution
SELECT t.*
FROM #mytable AS t
ORDER BY -PATINDEX('international%', t.[name]);
Note too that you can add a persisted computed column for -PATINDEX('international%', t.[name]) to speed things up.
Is it possible to SELECT * but without n-th column, for example 2nd?
I have some view that have 4 and 5 columns (each has different column names, except for the 2nd column), but I do not want to show the second column.
SELECT * -- how to prevent 2nd column to be selected?
FROM view4
WHERE col2 = 'foo';
SELECT * -- how to prevent 2nd column to be selected?
FROM view5
WHERE col2 = 'foo';
without having to list all the columns (since they all have different column name).
The real answer is that you just can not practically (See LINK). This has been a requested feature for decades and the developers refuse to implement it. The best practice is to mention the column names instead of *. Using * in itself a source of performance penalties though.
However, in case you really need to use it, you might need to select the columns directly from the schema -> check LINK. Or as the below example using two PostgreSQL built-in functions: ARRAY and ARRAY_TO_STRING. The first one transforms a query result into an array, and the second one concatenates array components into a string. List components separator can be specified with the second parameter of the ARRAY_TO_STRING function;
SELECT 'SELECT ' ||
ARRAY_TO_STRING(ARRAY(SELECT COLUMN_NAME::VARCHAR(50)
FROM INFORMATION_SCHEMA.COLUMNS
WHERE TABLE_NAME='view4' AND
COLUMN_NAME NOT IN ('col2')
ORDER BY ORDINAL_POSITION
), ', ') || ' FROM view4';
where strings are concatenated with the standard operator ||. The COLUMN_NAME data type is information_schema.sql_identifier. This data type requires explicit conversion to CHAR/VARCHAR data type.
But that is not recommended as well, What if you add more columns in the long run but they are not necessarily required for that query?
You would start pulling more column than you need.
What if the select is part of an insert as in
Insert into tableA (col1, col2, col3.. coln) Select everything but 2 columns FROM tableB
The column match will be wrong and your insert will fail.
It's possible but I still recommend writing every needed column for every select written even if nearly every column is required.
Conclusion:
Since you are already using a VIEW, the simplest and most reliable way is to alter you view and mention the column names, excluding your 2nd column..
-- my table with 2 rows and 4 columns
DROP TABLE IF EXISTS t_target_table;
CREATE TEMP TABLE t_target_table as
SELECT 1 as id, 1 as v1 ,2 as v2,3 as v3,4 as v4
UNION ALL
SELECT 2 as id, 5 as v1 ,-6 as v2,7 as v3,8 as v4
;
-- my computation and stuff that i have to messure, any logic could be done here !
DROP TABLE IF EXISTS t_processing;
CREATE TEMP TABLE t_processing as
SELECT *, md5(t_target_table::text) as row_hash, case when v2 < 0 THEN true else false end as has_negative_value_in_v2
FROM t_target_table
;
-- now we want to insert that stuff into the t_target_table
-- this is standard
-- INSERT INTO t_target_table (id, v1, v2, v3, v4) SELECT id, v1, v2, v3, v4 FROM t_processing;
-- this is andvanced ;-)
INSERT INTO t_target_table
-- the following row select only the columns that are pressent in the target table, and ignore the others.
SELECT r.* FROM (SELECT to_jsonb(t_processing) as d FROM t_processing) t JOIN LATERAL jsonb_populate_record(NULL::t_target_table, d) as r ON TRUE
;
-- WARNING : you need a object that represent the target structure, an exclusion of a single column is not possible
For columns col1, col2, col3 and col4 you will need to request
SELECT col1, col3, col4 FROM...
to omit the second column. Requesting
SELECT *
will get you all the columns
I am having this table of words from multiple files. I want to count how many files each word shows. I can that with the piece of code below. But when I nest it with the CREATE TABLE statement, it won't work. The second piece of code below is the error code.
SELECT WORD, COUNT(*) FROM (select DISTINCT ABSTRACTID, WORD FROM NSFABSTRACTS)
GROUP BY WORD ORDER BY COUNT(*) DESC
CREATE TABLE DOC_FREQ (WORD, TOTALCOUNT) AS
(
SELECT WORD, COUNT(*) FROM (select DISTINCT ABSTRACTID, WORD FROM NSFABSTRACTS)
GROUP BY WORD ORDER BY COUNT(*));
Here is the error message:
SQL Error: ORA-00907: missing right parenthesis
00907. 00000 - "missing right parenthesis"
*Cause:
*Action:
Can anyone suggest how to create this table? Thanks.
You cannot use order by when you have the query enclosed in parentheses; at least if that clause is also within the parentheses:
create table t42 as (select * from dual order by dummy);
SQL Error: ORA-00907: missing right parenthesis
It is allowed outside:
create table t42 as (select * from dual) order by dummy;
table T42 created.
You can remove the parentheses as they aren't needed at all here:
create table t42 as select * from dual order by dummy;
table T42 created.
Or remove the order by, since an order by in the create statement usually makes little difference and doesn't affect how the data is retrieved:
create table t42 as (select * from dual);
table T42 created.
Or preferably for my tastes, both:
create table t42 as select * from dual;
table T42 created.
I thought I understood how I can do a SELECT from the results of another SELECT statement, but there seems to be some sort of blurring of scope that I don't understand. I am using SQL Server 2008R2.
It is easiest to explain with an example.
Create a table with a single nvarchar column - load the table with a single text value and a couple of numbers:
CREATE TABLE #temptable( a nvarchar(30) );
INSERT INTO #temptable( a )
VALUES('apple');
INSERT INTO #temptable( a )
VALUES(1);
INSERT INTO #temptable( a )
VALUES(2);
select * from #temptable;
This will return: apple, 1, 2
Use IsNumeric to get only the rows of the table that can be cast to numeric - this will leave the text value apple behind. This works fine.
select cast(a as int) as NumA
from #temptable
where IsNumeric(a) = 1 ;
This returns: 1, 2
However, if I use that exact same query as an inner select, and try to do a numeric WHERE clause, it fails saying cannot convert nvarchar value 'apple' to data type int. How has it got the value 'apple' back??
select
x.NumA
from
(
select cast(a as int) as NumA
from #temptable
where IsNumeric(a) = 1
) x
where x.NumA > 1
;
Note that the failing query works just fine without the WHERE clause:
select
x.NumA
from
(
select cast(a as int) as NumA
from #temptable
where IsNumeric(a) = 1
) x
;
I find this very surprising. What am I not getting? TIA
If you take a look at the estimated execution plan you'll find that it has optimized the inner query into the outer and combined the WHERE clauses.
Using a CTE to isolate the operations works (in SQL Server 2008 R2):
declare #temptable as table ( a nvarchar(30) );
INSERT INTO #temptable( a )
VALUES ('apple'), ('1'), ('2');
with Numbers as (
select cast(a as int) as NumA
from #temptable
where IsNumeric(a) = 1
)
select * from Numbers
The reason you are getting this is fair and simple. When a query is executed there are some steps that are being followed. This is a parse, algebrize, optimize and compile.
The algebrize part in this case will get all the objects you need for this query. The optimize will use these objects to create a best query plan which will be compiled and executed...
So, when you look into that part you will see it will do a table scan on #temptable. And #temptable is defined as the way you created your table. That you will do some compute on it is a different thing..... The column still has the nvarchar datatype..
To know how this works you have to know how to read a query. First all the objects are retrieved (from table, inner join table), then the predicates (where, on), then the grouping and such, then the select of the columns (with the cast) and then the orderby.
So with that in mind, when you have a combination of selects, the optimizer will still process it that way.. since your select is subordinate to the from and join parts of your query, it will be a reason for getting this error.
I hope i made it a little clear?
The optimizer is free to move expressions in the query plan in order to produce the most cost efficient plan for retrieving the data (the evaluation order of the predicates is not guaranteed). I think using the case expression like bellow produces a NULL in absence of the ELSE clause and thus takes the APPLE out
select a from #temptable where case when isnumeric(a) = 1 then a end > 1