MySql ya mwaka upi unatumia, na front end unatumia ipi?
coz wakati mwingine inategemeana na version ipi unatumia ya MySql vs front end.
coming to you soon with a solution.
Nafikiri version ni 3.13.58 kitu ka hicho maana saizi sipo home nikirudi nitacheck sawa.Lakini nafikiri ni hiyo.
MySql ya mwaka upi unatumia, na front end unatumia ipi?
coz wakati mwingine inategemeana na version ipi unatumia ya MySql vs front end.
tukija kwenye jinsi ya kutumia EXISTS:
SELECT *
FROM klienci
WHERE EXISTS (
SELECT adres
FROM klienci
WHERE id = '1'
)
kwanza kabisa hii query itaanza kua executed kwenye mabano:
(
SELECT adres
FROM klienci
WHERE id = '1'
)
then baada ya kuona kwamba query inareturn rows ndio itakwenda kwenye EXISTS condition.
kwamfano ikiwa query hii ikakupa result, then EXISTS condition itakua executed na itareturn rows zote kutoka kwenye table ya klienci.
kwamahesabu ya haraka haraka nadhani utakua umekosea kwenye datatype. naitilia mashaka hiyo column ya id, inaweza ikawa umedeclare as integer lakini hapa umeandika as 'varchar' cheki hapa: WHERE id = '1'
hebu jaribu kutumia hizi data hapa chini kwenye mysql yako kisha unijuze kama umepata result ama vipi, nimejaribu kutumia simple query inayofanana na yako.
ukipata result then jaribu kucompare na query yako uone tatizo likwapi.
JUST COPY AND PASTE INTO QUERY ANALZER AND RUN IT.
CREATE TABLE Books
(
BookID SMALLINT NOT NULL PRIMARY KEY,
BookTitle VARCHAR(60) NOT NULL,
Copyright varchar(10)
)
INSERT INTO Books VALUES (12786, 'Java',1934)
INSERT INTO Books VALUES (13331, 'MySQL',1919)
INSERT INTO Books VALUES (14356, 'PHP',1966)
INSERT INTO Books VALUES (15729, 'PERL',1932)
INSERT INTO Books VALUES (16284, 'Oracle',1996)
INSERT INTO Books VALUES (17695, 'Pl/SQL',1980)
INSERT INTO Books VALUES (19264, 'JavaScript',1992)
INSERT INTO Books VALUES (19354, 'Vb.NET', 1993)
RKisha malizia kwa run hii query hapa chini
SELECT *
FROM books
WHERE EXISTS (
SELECT bookid
FROM books
WHERE bookid = 12786
)
EXIST haiko suported na version za MySQL < 4.1 . Jaribu ku-upgrade utumia latest MySQL version.
Sina uhakika unajaribu kufanya nini, lakini pengine hii inaweza kufanya unachotaka kufanya hapo:
SELECT a.* FROM klienci as a
LEFT JOIN klienci as b
WHERE b.id='1' AND b.id IS NOT NULL
Mkuu asante nafikiri pia tatizo ni version.
Nachotaka kufanya ni ,mfano kunakuwa na table la data za mteja na table la oder za mteja,hivyo sitaki kuingiza redandati data za mteja,hivyo nachotaka kufanya ni inacheck kama huyo mteja ana exist basi i update order table tu na kama ha exists i update table zote.ktk shema
Mkuu asante nafikiri pia tatizo ni version.
Nachotaka kufanya ni ,mfano kunakuwa na table la data za mteja na table la oder za mteja,hivyo sitaki kuingiza redandati data za mteja,hivyo nachotaka kufanya ni inacheck kama huyo mteja ana exist basi i update order table tu na kama ha exists i update table zote.ktk shema
Nime data structure ya table yako na kile unachotaka kufanya na nitafanya simulation sasa hivi.
Nadhani solution nzuri ni kufanya hili nje ya MySQL. Kabla huja insert new order, check kama client yupo tayari.
Kama yupo, perform a query kupata id ya client huyo, e.g. select client_id from client where client_name='Client name kutoka kwenye form'. Kama hayupo, insert client kwanza na tumia mysql_insert_id kupata id ya huyo client mpya.
Baada ya kuwa na id ya client, unaweza sasa ku insert hiyo order yako, ukiwa umeweka client_id field ya order hiyo sawasawa.
Unatumia programming language gani?
Mkuu nasubiri hiyo kitu
MkamaP:
Kutokana na posti yako ya kwanza, database parser ime-respond kuwa kuna syntax error. Syntax error inaonyesha kuwa umekosea kuandika query yenyewe. Hivyo inawezekana sio tatizo la version.
Sasa tuje kwenye uchambuzi wa SQL statement. Kumbuka kuwa database table ni set. Na queries ni instanties za table.
Statement hii SELECT * FROM klienci ni query inayorudisha instant au temporary table yenye data structure sawa na table klient.
Statement SELECT adres FROM klienci ni query yenye kurudisha instant au temporary table yenye data structure tofauti na table klient. Hii ni new table yenye column moja tu inayoitwa adres. Hivyo kuna uwezekano mkubwa kuwa database engine inashindwa kulinganisha table klienci na temporary table yenye column moja tu.
Hivyo ningeomba ujaribu:
SELECT *
FROM klienci
WHERE EXISTS (
SELECT *
FROM klienci
WHERE id = '1'
)
Select statement iliyo ndani ya mabano ina data structure sawa na table klienci iliyopo nje. Sijuhi kama hii itasaidia.
Mkuu nashukuru kwa maelekezo yako murua,nilitoka kidogo .
Nina swali jingine hapa.
mfano ktk table yangu na attribute hizi-
,type _of_product,vendor_name, model.Sasa hapa nataka quel ambayo itatoa bidhaa zote(type_of_product) kutoka kwa ma vendor wote.na kila product iwe na attribute yani ,type _of_product,vendor_name, model, na product zijipange kutokana na type_of_product according to vendor_name.
Mkuu natumia PHP