sql - Delete all duplicate records from Oracle table except oldest -

-

i have 2 tables, 1 parent tablea , 1 child tableb. tableb has 1 or more records parent record in tablea. need delete records tableb except earliest date i.e. duplicates in tableb. don't think tablea needs involved in statement i'm including reference.

tablea  _______  secid, secname  1,     sec1 2,     sec2 3,     sec3 4,     sec4  tableb _________ incid, secid, paydate  16,    1,     11/03/2011 17,    1,     11/04/2011 18,    2,     10/01/2011 19,    3,     01/06/2011 20,    3,     01/09/2011 21,    3,     01/12/2011 22,    4,     10/06/2011

so in tableb above need delete records 17, 20, , 21 leaving 1 record each secid. far have below reason it's including earliest record want keep:

delete tableb paydate not in (   select min(paydate)from tableb   having ( count(paydate) > 1 ) )

you can use rowid , analytics:

sql> delete tableb   2   rowid not in   3           (select first_value(rowid)over(partition secid order paydate)   4              tableb);  3 rows deleted  sql> select * tableb;       incid      secid paydate ---------- ---------- -----------         16          1 11/03/2011         18          2 10/01/2011         19          3 01/06/2011         22          4 10/06/2011

you use more conventional semi-join:

sql> delete tableb b_out   2   exists (select null   3                   tableb b_in   4                  b_in.secid = b_out.secid   5                    , b_in.paydate < b_out.paydate);  3 rows deleted

Comments

Post a Comment

Popular posts from this blog

Javascript line number mapping -

-
magically formatted comments change reported line number of javascript errors in browsers; this: //@line n "f" n line number , f file name. unfortunately, //@line appears ungoogleable. know there documentation on feature, , browsers support it? (i found references here , here .) from can find available in mozilla based browsers. it using js_setoptions command can turn these options on or off depending on values passed. https://developer.mozilla.org/en/js_setoptions
Read more

c# - Is it possible to remove an existing registration from Autofac container builder? -

-
something along lines: builder.registertype<mytype>().as<itype>(); builder.registertype<mytype2>().as<itype>(); builder.deregistertype<mytype>().as<itype>() var container = builder.build(); var types = container.resolve<ienumerable<itype>>(); assert.istrue(types.count == 1); assert.istrue(types[0].gettype == typeof(mytype2)); scenario: go through bunch of assemblies , go register types want make sure have 1 implementation of given type. need before create container. track on own nice if autofac me bit. this cannot done directly using containerbuilder , unless start on new one. mind you, having first built container should able construct new container filtering away unwanted types , reusing registrations first container. this: ... var container = builder.build(); builder = new containerbuilder(); var components = container.componentregistry.registrations .where(cr => cr.activator.limittype != typ...
Read more

php - Mysql PK and FK char(36) vs int(10) -

-
i have read mysql can handle indexes , searches better if tables keys integers rather char(36) uuid's. is worth converting int(10)? note: use 1 server , have have plans use multiple databases concurrently therefore removing 1 of big reasons using uuid. our tables innodb if makes difference. thanks in advance. usually rdbms can handle integer keys pk more efficient, other datatypes. reason how build index column, yes: long dont require string (or other typed) keys, should use integers. however: char(36) , int(10) far away being equal, because int(10) much smaller, char(36). dont know, if require many different keys, should keep in mind. update, complete last paragraph: int(10) 32-bit, char(36) 36 - ^byte^ (= 288-bit). not mean, int consumes less space, means, char(36) has 4 times more different keys.
Read more