大约有 37,000 项符合查询结果（耗时：0.0317秒） [XML]
Query for documents where array size is greater than 1
... @Tobia my first use was $exists only but it actually use whole table scan so very slow. db.test.find({"name":"abc","d.5":{$exists:true},"d.6":{$exists:true}}) "nReturned" : 46525, "executionTimeMillis" : 167289, "totalKeysExamined" : 10990840, "totalDocsExamined" : 10990840, ...
How do I see active SQL Server connections?
...ys.sysprocesses WHERE dbid > 0
--Available connections
DECLARE @SPWHO1 TABLE (DBName VARCHAR(1000) NULL, NoOfAvailableConnections VARCHAR(1000) NULL, LoginName VARCHAR(1000) NULL)
INSERT INTO @SPWHO1
SELECT db_name(dbid), count(dbid), loginame FROM sys.sysprocesses WHERE dbid > 0 GROUP B...
Unique constraint that allows empty values in MySQL
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@MianAnjum bolded: CREATE TABLE table (key int(11) NOT NULL AUTO_INCREMENT, field tinyint(1) DEFAULT NULL)
– Paul Nowak
Sep 19 '17 at 19:45
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How to convert SQL Query result to PANDAS Data Structure?
...ctor not properly called!, it appears that the tuple of tuples is not acceptable for DataFrame constructor. There is also no .keys() on cursor either in dictionary or tuple mode.
– Mobigital
Jan 20 '19 at 20:45
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Storing sex (gender) in database
...the 'closest' data type would be tinyint with a CHECK constraint or lookup table as appropriate.
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SQL how to make null values come last when sorting ascending
I have a SQL table with a datetime field. The field in question can be null. I have a query and I want the results sorted ascendingly by the datetime field, however I want rows where the datetime field is null at the end of the list, not at the beginning.
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hexadecimal string to byte array in python
...hex(hex_string)
bytearray(b'\xde\xad\xbe\xef')
Note that bytes is an immutable version of bytearray.
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How can I get a list of all functions stored in the database of a particular schema in PostgreSQL?
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After some searching, I was able to find the information_schema.routines table and the information_schema.parameters tables. Using those, one can construct a query for this purpose. LEFT JOIN, instead of JOIN, is necessary to retrieve functions without parameters.
SELECT routines.routine_name, pa...
How do you convert a byte array to a hexadecimal string, and vice versa?
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Text: 718,380.63 (1.0X faster)
Sentence: 39.71 (1.0X faster)
Lookup tables have taken the lead over byte manipulation. Basically, there is some form of precomputing what any given nibble or byte will be in hex. Then, as you rip through the data, you simply look up the next portion to see what...
Why is the Fibonacci series used in agile planning poker? [closed]
...nd verbal description in the software domain is closer to the one shown in Table 3 than to Saaty’s." And in this table we see that something is called "slightly bigger" if it is 125% of the base size and it is called "bigger", if it is 175% of the base size.
– asmaier
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