大约有 40,000 项符合查询结果（耗时：0.0131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.
...
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...
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 &...
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...
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 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_...
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...
SQL Server: What is the difference between CROSS JOIN and FULL OUTER JOIN?
...
select COUNT_BIG(*) FROM Traffic t CROSS JOIN Recipient r and SELECT COUNT_BIG(*) FROM Traffic t FULL JOIN Recipient r ON (1=1) they are the same.
– urlreader
Sep 20 '13 at 21:02
...