大约有 40,000 项符合查询结果（耗时：0.0203秒） [XML]
Simplest way to do a recursive self-join?
...
WITH q AS
(
SELECT *
FROM mytable
WHERE ParentID IS NULL -- this condition defines the ultimate ancestors in your chain, change it as appropriate
UNION ALL
SELECT m.*
FROM mytable m
...
SQL is null and = null [duplicate]
...e t (x int, y int);
insert into t values (null, null), (null, 1), (1, 1);
select 'x = null' as test , x, y from t where x = null
union all
select 'x != null', x, y from t where x != null
union all
select 'not (x = null)', x, y from t where not (x = null)
union all
select 'x = y', x, y from t where ...
When to use Common Table Expression (CTE)
...ing well? Can someone give me a simple example of limitations with regular select, derived or temp table queries to make the case of CTE? Any simple examples would be highly appreciated.
...
Purpose of Unions in C and C++
... @legends2k: any decent optimizer will recognize bitwise operations that select an entire byte and generate code to read/write the byte, same as the union but well-defined (and portable). e.g. uint8_t getRed() const { return colour & 0x000000FF; } void setRed(uint8_t r) { colour = (colour &...
Multiple select statements in Single query
...
SELECT (
SELECT COUNT(*)
FROM user_table
) AS tot_user,
(
SELECT COUNT(*)
FROM cat_table
) AS tot_cat,
(
SELECT COUNT(*)
FROM course_table
) AS tot_course
...
How to change identity column values programmatically?
...ITY(1,1) PRIMARY KEY,
X VARCHAR(10)
)
INSERT INTO Test
OUTPUT INSERTED.*
SELECT 'Foo' UNION ALL
SELECT 'Bar' UNION ALL
SELECT 'Baz'
Then you can do
/*Define table with same structure but no IDENTITY*/
CREATE TABLE Temp
(
ID INT PRIMARY KEY,
X VARCHAR(10)
)
/*Switch table metadata to new struct...
FIND_IN_SET() vs IN()
...
SELECT name
FROM orders,company
WHERE orderID = 1
AND companyID IN (attachedCompanyIDs)
attachedCompanyIDs is a scalar value which is cast into INT (type of companyID).
The cast only returns numbers up to the...
How can I list ALL grants a user received?
...ust direct table grants (e.g., grants via roles, system privileges such as select any table, etc.), here are some additional queries:
System privileges for a user:
SELECT PRIVILEGE
FROM sys.dba_sys_privs
WHERE grantee = <theUser>
UNION
SELECT PRIVILEGE
FROM dba_role_privs rp JOIN role_...
What are Aggregates and PODs and how/why are they special?
...ns (10.3) and no virtual base classes (10.1), and
— the constructor selected to copy/move each direct base class subobject is trivial, and
— for each non-static data member of X that is of class type (or array thereof), the constructor
selected to copy/move that member is trivial;
...
Inserting multiple rows in a single SQL query? [duplicate]
...much better methods as seen in the other answers.
You can use INSERT with SELECT UNION ALL:
INSERT INTO MyTable (FirstCol, SecondCol)
SELECT 'First' ,1
UNION ALL
SELECT 'Second' ,2
UNION ALL
SELECT 'Third' ,3
...
Only for small datasets though, which should be fine for your 4 rec...