大约有 40,000 项符合查询结果（耗时：0.0272秒） [XML]
Select rows which are not present in other table
...task, all of them standard SQL.
NOT EXISTS
Often fastest in Postgres.
SELECT ip
FROM login_log l
WHERE NOT EXISTS (
SELECT -- SELECT list mostly irrelevant; can just be empty in Postgres
FROM ip_location
WHERE ip = l.ip
);
Also consider:
What is easier to read in EXISTS...
Unable to find valid certification path to requested target - error even after cert imported
... main(String[] args) throws Exception {
String host;
int port;
char[] passphrase;
if ((args.length == 1) || (args.length == 2)) {
String[] c = args[0].split(":");
host = c[0];
port = (c.length == 1) ? 443 : Integer.parseInt(c[1]);
String p = (args.leng...
What does “@private” mean in Objective-C?
...lic
int publicNumber;
@protected // Protected is the default
char protectedLetter;
@private
BOOL privateBool;
}
@end
@implementation MyFirstClass
- (id)init {
if (self = [super init]) {
publicNumber = 3;
protectedLetter = 'Q';
privateBool = NO;
...
Find rows with multiple duplicate fields with Active Record, Rails & Postgres
...
Tested & Working Version
User.select(:first,:email).group(:first,:email).having("count(*) > 1")
Also, this is a little unrelated but handy. If you want to see how times each combination was found, put .size at the end:
User.select(:first,:email).gro...
How do I put an 'if clause' in an SQL string?
... WHERE purchaseOrder_ID = '@purchaseOrder_ID' and
not exists (SELECT *
FROM itemsOrdered WHERE purchaseOrder_ID = '@purchaseOrdered_ID' AND status = 'PENDING'
)
However, I might guess that you are looping at a higher level. To set all such v...
'IF' in 'SELECT' statement - choose output value based on column values
...
SELECT id,
IF(type = 'P', amount, amount * -1) as amount
FROM report
See http://dev.mysql.com/doc/refman/5.0/en/control-flow-functions.html.
Additionally, you could handle when the condition is null. In the case of...
How to find the size of localStorage
...ntil DevTools are opened)
Opera 12.15 ~4212ms /3.55Mb (this is when 5Mb is selected, but Opera asks nicely if we want increase the amount of lS, unfortunately it crashes if test conducted a few times in a row)
Win 8 (Under Parallels 8)
IE10 ~7850ms /9.54Mb
...
When to use EntityManager.find() vs EntityManager.getReference() with JPA
... }
}
If i call find method, JPA provider, behind the scenes, will call
SELECT NAME, AGE FROM PERSON WHERE PERSON_ID = ?
UPDATE PERSON SET AGE = ? WHERE PERSON_ID = ?
If i call getReference method, JPA provider, behind the scenes, will call
UPDATE PERSON SET AGE = ? WHERE PERSON_ID = ?
And ...
Convert integer to hexadecimal and back again
...ur hex to int solution will produce SIGNED integers and maxes out at 8 hex chars.
– Scott Solmer
Mar 8 '16 at 19:24
|
show 5 more comments
...
Execute Insert command and return inserted Id in Sql
...md=new SqlCommand("INSERT INTO Mem_Basic(Mem_Na,Mem_Occ) VALUES(@na,@occ);SELECT SCOPE_IDENTITY();",con))
{
cmd.Parameters.AddWithValue("@na", Mem_NA);
cmd.Parameters.AddWithValue("@occ", Mem_Occ);
con.Open();
int modified = Convert.ToInt32(cmd.ExecuteScalar());...