大约有 48,000 项符合查询结果（耗时：0.0404秒） [XML]
SQL SELECT speed int vs varchar
...k: A=261MB B=292MB C=322MB
Non-indexed by id: select count(*), select by id: 450ms same on all tables
Insert* one row per TX: B=9ms/record C=9ms/record
Bulk insert* in single TX: B=140usec/record C=180usec/record
Indexed by id, select by id: B=about 2...
LINQ to SQL - Left Outer Join with multiple join conditions
...g.Where(f => f.otherid == 17).DefaultIfEmpty()
where p.companyid == 100
select f.value
Or you could use a subquery:
from p in context.Periods
join f in context.Facts on p.id equals f.periodid into fg
from fgi in (from f in fg
where f.otherid == 17
select f).DefaultIfE...
Better techniques for trimming leading zeros in SQL Server?
...
Why don't you just cast the value to INTEGER and then back to VARCHAR?
SELECT CAST(CAST('000000000' AS INTEGER) AS VARCHAR)
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0
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How can I get column names from a table in SQL Server?
... much more by querying the Information Schema views.
This sample query:
SELECT *
FROM INFORMATION_SCHEMA.COLUMNS
WHERE TABLE_NAME = N'Customers'
Can be made over all these DB objects:
CHECK_CONSTRAINTS
COLUMN_DOMAIN_USAGE
COLUMN_PRIVILEGES
COLUMNS
CONSTRAINT_COLUMN_USAGE
CONSTRAINT_...
mysql :: insert into table, data from another table?
...
INSERT INTO action_2_members (campaign_id, mobile, vote, vote_date)
SELECT campaign_id, from_number, received_msg, date_received
FROM `received_txts`
WHERE `campaign_id` = '8'
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How do we count rows using older versions of Hibernate (~2009)?
...eturn int and use this form:
int count = ((Long)getSession().createQuery("select count(*) from Book").uniqueResult()).intValue();
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Need to list all triggers in SQL Server database with table name and table's schema
...
Here's one way:
SELECT
sysobjects.name AS trigger_name
,USER_NAME(sysobjects.uid) AS trigger_owner
,s.name AS table_schema
,OBJECT_NAME(parent_obj) AS table_name
,OBJECTPROPERTY( id, 'ExecIsUpdateTrigger') AS isupda...
Selecting empty text input using jQuery
...ow do I identify empty textboxes using jQuery? I would like to do it using selectors if it is at all possible. Also, I must select on id since in the real code where I want to use this I don't want to select all text inputs.
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How to make HTML Text unselectable [duplicate]
I would like to add text to my webpage as a label and make it unselectable.
4 Answers
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How to see indexes for a database or table in MySQL?
...pecific schema you can use the STATISTICS table from INFORMATION_SCHEMA:
SELECT DISTINCT
TABLE_NAME,
INDEX_NAME
FROM INFORMATION_SCHEMA.STATISTICS
WHERE TABLE_SCHEMA = 'your_schema';
Removing the where clause will show you all indexes in all schemas.
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