It's been a while since I've spoken MySQL... but I'd do it this way
But the ALTER TABLE syntax (the first one) should get you the same result. If not, you can always drop and re-create the index.
It would be interesting tho to see the comparison of the execution timing and EXPLAIN plan with and without the indices.
And if you want to optimize further, here's an article on how to use the MySQL profiler.
Hi,
I have a file with multiple records...and I have to select records based on first column....here is the sample file...
I01,abc,125,1a2,LBVI02
I01,abc,126,2b5,LBVI02
I02,20070530,254,abc,LLBI01
I02,20070820,111,bvd,NGBI01
I need all records with I01 in first field in one file and... (8 Replies)
hi..
i need to optimize my select query ..
my situation is like this ..
i have 15 lac recors in my table..
the following query takes nine seconds to give the required output..
SELECT max(ah.AUC_AMT),
SUBSTRING_INDEX(GROUP_CONCAT(SUBSTRING_INDEX(ah.AUC_CUS_NAME,'@',1) order by AUC_AMT... (0 Replies)
hi..
i need to optimize my select query ..
my situation is like this ..
i have 15 lac recors in my table..
the following query takes nine seconds to give the required output..
SELECT max(ah.AUC_AMT),
SUBSTRING_INDEX(GROUP_CONCAT(SUBSTRING_INDEX(ah.AUC_CUS_NAME,'@',1) order by AUC_AMT... (1 Reply)
Hi, I would just like to know how to get the file with the max filename on a directory and get rid of all the others. For example, in directory A:/ i have the ff files:
APPLE2001
APPLE2002
APPLE2003
GRAPE2004
what I want to get is the max in files whose filenames start with APPLE*,... (4 Replies)
I have a file with 3 columns
I want to get the record with the max salary. If there are more than 1 record having the highest salary, i want any one of them.
empid,ename,Sal
1,abc,100
2,def,200
3,xyz,300
4,pqr,100
5,mnq,300
Output
Any record with 300 as salary
Please use next... (1 Reply)
I feel stupid for asking this because it seems that MYSQL code isn't working the way that I think it should work.
Basically I wrote code like this:
select * from `Test_DC_Trailer` HAVING max(DR_RefKey);
Where the DR_RefKey is a unique numeric field that is auto iterated (like a primary key)... (7 Replies)
I want records which have more than one and different value in the second column on the below sample file.
Ex, I have the samle file below :-
XYZ 1
XYZ 3
abc 1
abc 1
qwe 2
qwe 1
qwe 3
I want to select XYZ and QWE line only. (6 Replies)
Dear community,
I woul like to make a query to output all the users having the same IP address.
The table is somethig like:
name logged_ip
==== =========
user1 127.0.0.1
user2 127.0.0.2
user3 127.0.0.3
user4 127.0.0.1
user5 127.0.0.2
user6 127.0.0.5I used this query... (4 Replies)
Hello,
I am working on an application that uses allot of memory depending on the input. I am also working on more than one processing algorithm.
The program has a long processing time (hours) so it would be nice to be able to monitor the maximum memory footprint of the application during runs... (1 Reply)
Discussion started by: LMHmedchem
1 Replies
LEARN ABOUT DEBIAN
sqlt-diff
SQLT-DIFF(1p) User Contributed Perl Documentation SQLT-DIFF(1p)NAME
sqlt-diff - find the differences b/w two schemas
SYNOPSIS
For help:
sqlt-diff -h|--help
For a list of all valid parsers:
sqlt -l|--list
To diff two schemas:
sqlt-diff [options] file_name1=parser1 file_name2=parser2
Options:
-d|--debug Show debugging info
-t|--trace Turn on tracing for Parse::RecDescent
-c|--case-insensitive Compare tables/columns case-insensitively
--ignore-index-names Ignore index name differences
--ignore-constraint-names Ignore constraint name differences
--mysql_parser_version=<#####> Specify a target MySQL parser version
for dealing with /*! comments
--output-db=<Producer> This Producer will be used instead of one
corresponding to parser1 to format output
for new tables
--ignore-view-sql Ignore view SQL differences
--ignore-proc-sql Ignore procedure SQL differences
--no-batch-alters Do not clump multile alters to the same table into a
single ALTER TABLE statement where possible.
--quote=<character> Use <character> to quote all table and field
names in statements
DESCRIPTION
sqlt-diff is a utility for creating a file of SQL commands necessary to transform the first schema provided to the second. While not yet
exhaustive in its ability to mutate the entire schema, it will report the following
o New tables
Using the Producer class of the target (second) schema, any tables missing in the first schema will be generated in their entirety
(fields, constraints, indices).
o Missing/altered fields
Any fields missing or altered between the two schemas will be reported as:
ALTER TABLE <table_name>
[DROP <field_name>]
[CHANGE <field_name> <datatype> (<size>)] ;
o Missing/altered indices
Any indices missing or of a different type or on different fields will be indicated. Indices that should be dropped will be reported
as such:
DROP INDEX <index_name> ON <table_name> ;
An index of a different type or on different fields will be reported as a new index as such:
CREATE [<index_type>] INDEX [<index_name>] ON <table_name>
( <field_name>[,<field_name>] ) ;
ALTER, CREATE, DROP statements are created by SQL::Translator::Producer::*, see there for support/problems.
Currently (v0.0900), only MySQL is supported by this code.
AUTHOR
Ken Youens-Clark <kclark@cpan.org>.
SEE ALSO
SQL::Translator, <http://sqlfairy.sourceforge.net>.
perl v5.14.2 2012-01-18 SQLT-DIFF(1p)