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select * vs select column
If I just need 2/3 columns and I query SELECT * instead of providing those columns in select query, is there any performance degradation regarding more/less I/O or memory?
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How do I change db schema to dbo
...which will generate a set of ALTER sCHEMA statements for all your talbes:
SELECT 'ALTER SCHEMA dbo TRANSFER ' + TABLE_SCHEMA + '.' + TABLE_NAME
FROM INFORMATION_SCHEMA.TABLES WHERE TABLE_SCHEMA = 'jonathan'
You then have to copy and run the statements in query analyzer.
Here's an older script t...
Enable binary mode while restoring a Database from an SQL dump
...ease follows the preceding steps.
Open file in notepad.
Click on Save as
Select Encoding type UTF-8.
Now source your db.
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PHP code to convert a MySQL query to CSV [closed]
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SELECT * INTO OUTFILE "c:/mydata.csv"
FIELDS TERMINATED BY ',' OPTIONALLY ENCLOSED BY '"'
LINES TERMINATED BY "\n"
FROM my_table;
(the documentation for this is here: http://dev.mysql.com/doc/refman/5.0/en/select.html)
or:...
Determine which MySQL configuration file is being used
Is there a command to determine which configuration file MySQL 5.0 is currently using?
15 Answers
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Split function equivalent in T-SQL?
...AR(2048) = 'Mike/John/Miko/Matt'; DECLARE CaracString NVARCHAR(1) = '/'; SELECT * FROM dbo.FnSplitString (VarString, CaracString)
– fernando yevenes
Feb 8 '19 at 15:57
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Best way to test if a row exists in a MySQL table
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You could also try EXISTS:
SELECT EXISTS(SELECT * FROM table1 WHERE ...)
and per the documentation, you can SELECT anything.
Traditionally, an EXISTS subquery starts with SELECT *, but it could
begin with SELECT 5 or SELECT column1 or anything ...
如何查看Oracle用户的SQL执行历史记录？ - 数据库(内核) - 清泛网 - 专注C/...
如何查看Oracle用户的SQL执行历史记录？select * from v$sqlarea t order by t LAST_ACTIVE_TIME desc注意 ：执行此语句等等一些相关的语句 必须具有DBA 的权限 虽然
select * from v$sqlarea t order by t.LAST_ACTIVE_TIME desc
注意 ：执行此语句等等一些相...
mysql_fetch_array()/mysql_fetch_assoc()/mysql_fetch_row()/mysql_num_rows etc… expects parameter 1 to
I am trying to select data from a MySQL table, but I get one of the following error messages:
31 Answers
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What are the options for storing hierarchical data in a relational database? [closed]
...lies? Perform a traversal on both sub-trees computing the intersection and union of the two sub-trees. The percent similar is the intersection divided by the union.
Transitive Closure: Walk the sub-tree and sum up the field(s) of interest, e.g. "How much aluminum is in a sub-assembly?"
Yes, you ca...