Re: Changing a field's data in every record

On Sat, 18 Feb 2017, debt wrote: How does one "grab" the existing data and then change it? Can this be done solely in MySQL I am not sure to understand your question ... you usually manipulate data inside mysql ... but here it seems to me you are not talking of changing the d

using indices with SMALL tables

Y A FACTOR 736. Now what had taken 38 minutes takes 3.02 sec !!! Great ! -- ---- Lucio Chiappetti - INAF/IASF - via Bassini 15 - I-20133 Milano (Italy) For more info : http://www.iasf-milan

Re: get row inserted time or modified time

On Tue, 2 Jun 2015, Selvam Gce wrote: Is there any way to get row inserted time or modified time in my mysql table??? if you define a column with any name and a type of timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP this will automatically timestamp each record (row

Re: Select one valuebut not the other

FIRST | 22 | | 22 |9 | no| 22 | | 24 | 20 | FIRST | 200004 | -- Lucio Chiappetti - INAF/IASF - via Bassini 15 - I-20133 Milano (Italy) For more info : http://www.iasf-milano.inaf.it/~lucio/personal.html

Re: store search result as new table in memory

table later to add them. if they are big, using proper indices is a must to get quick responses. -- Lucio Chiappetti - INAF/IASF - via Bassini 15 - I-20133 Milano (Italy) For more info : http://www.iasf-milano.inaf.it

Re: ssh basics

to issue a select into a table, and read back the output in an IDL structure) but I never managed to do it. But I did not try hard. -- -------- Lucio Chiappetti - INAF/IASF - via Bassini 15 - I-20133 Milano (Italy) For more i

Re: Users and Groups

same "logical group" -- -------- Lucio Chiappetti - INAF/IASF - via Bassini 15 - I-20133 Milano (Italy) For more info : http://www.iasf-milano.inaf.it/~lucio/personal.html Do not like Firefox

Re: mysql float data type

, REAL*8) get to about 16. So if a quantity needs high precision (typically this occurs for angular quantities where arcseconds are important), use double. -- ---- Lucio Chiappetti - INAF/IASF - via Bassini 15 - I-20133 Milano

Re: forum vs email

mers complain if one opens a new thread instead of posting in an existing one. -- ---- Lucio Chiappetti - INAF/IASF - via Bassini 15 - I-20133 Milano (Italy) Fo

RE: How MyISAM handle auto_increment

or thereabouts. -- ---- Lucio Chiappetti - INAF/IASF - via Bassini 15 - I-20133 Milano (Italy) Citizens entrusted of public functions have the duty to accom

Re: How MyISAM handle auto_increment

rts from 1. -- -------- Lucio Chiappetti - INAF/IASF - via Bassini 15 - I-20133 Milano (Italy) Citizens entrusted of public functions have the duty to accomplish them with discipline and honour [Art. 54 Constitut

Re: int(10) va int(11)

, but sometime affect also comparison and that's very annoying if you work usually with numbers like 1.43E-12 ! -- -------- Lucio Chiappetti - INAF/IASF - via Bassini 15 - I-20133 Mil

Re: Record old passwords ?

st no real life application (unless perhaps one is a spy) which really require this degree of security ! -- Lucio Chiappetti - INAF/IASF - via Bassini 15 - I-20133 Milano (

using Unix soft links

bably delete all tables and recreate them. But I wonder if there is anything intrinsically wrong in the usage of soft-links, or whether this might be an indication instead of hardware problems with our machine or disks ! -- Lucio Chiappetti - INAF/IASF - via Bassini 15 - I-20133 Mil

Re: optimizing UNIONs ?

writing the definition of the union of joins is slightly painful (but can be automatized). -- -------- Lucio Chiappetti - INAF/IASF - via Bassini 15 - I-20133 Milano (Ital

optimizing UNIONs ?

out making a physical copy of the union) i.e. to force proper usage of the various indices present in the individual tables ? It shall be noted that the various member tables are all of comparable length with just a few thousand records each. -- --

Re: excessive time spent in "statistics" status

of the members. And I've noticed that the result of EXPLAIN SELECT (the order) changed according to the content of the query (e.g. the particular WHERE condition). So for me experimentally use of SELECT STRAIGHT_JOIN is an effective solution. -- -----

Re: excessive time spent in "statistics" status

On Tue, 4 Sep 2007, Shawn Green wrote: > > On Tue, 4 Sep 2007, Lucio Chiappetti wrote: > > For each I tested 3 cases (total 16*3=48) : > > > > a) the query on the "virtual" table correlated with the external > > (the virtual is my G left join t1 ..

Re: excessive time spent in "statistics" status

On Tue, 4 Sep 2007, Lucio Chiappetti wrote: > I'll do some experimenting and report back. In lack of better ways of doing a tie-break, I've done the following tests (with the linemode client), checking both the results of a query and the total time spent. I tested 16 different co

Re: excessive time spent in "statistics" status

sion) optimizer_search_depth to a decent default (0 ?) once forever, because this requires no changes to the code (however if SELECT STRAIGHT_JOIN will require changes concentrated in a few places). I'll do some experimenting and report back. -- ---

Re: excessive time spent in "statistics" status

. On Sat, 1 Sep 2007, Shawn Green wrote: > Lucio Chiappetti wrote: > > I have some queries, involving a largish number of JOIN, which are > > [...] very slow or [...] remain in the "statistics" status [forever] > > This involved creating a working table G &

excessive time spent in "statistics" status

te that the bulk of the members are all joined with G), or introducing parentheses or with other syntax changes ? - or has it to do with some configuration parameter, maybe related to what is cached, cache size or other ? Thanks in ad

echoing comments in mysql (changed 4.0 to 5.0 ?)

ll our logging policy depends on that ! -- -------- Lucio Chiappetti - INAF/IASF - via Bassini 15 - I-20133 Milano (Italy) For more info : http://www.iasf-mil