MySQL muzisankha sankhani: zitsanzo zosankhidwazi woyendetsa

MySQL, monga ena ubale dongosolo lililonse kasamalidwe Nawonso achichepere, ali mu dongosolo ake chitsanzo Sankhani mawu. Zimenezi n'zosadabwitsa, chifukwa zinasokoneza makompyuta muli zachinsinsi kwenikweni kupeza pamene kutero. select from SELECT позволяет делать это множеством различных способов, предоставляя большой набор инструментов. MySQL muzisankha Sankhani mawu amalola kuchita izi mu njira zambiri zosiyana, kupereka akonzedwa kwambiri zipangizo.

khazikitsa MySQL

MySQL akuyendera pansi pa Windows, ndi pansi Linux. Kukhazikitsa MySQL Ubuntu, kuchita magulu awiri mwachilungamo pa osachiritsika a Os:

- Sudo oyenera-kupeza kukhazikitsa MySQL-Seva.

- Sudo oyenera-kupeza kukhazikitsa MySQL-kasitomala.

Pakuti MySQL Windows, monga kukopera ku malo olemekezeka "Nawonso achichepere" yoyenera unsembe phukusi ndi kuwathamangitsa iwo.

Angamulambirire ndi mawu Sankhani

Complete dongosolo mu MySQL kusankha mawu Sankhani ali motere:

1. Sankhani - maina ndime (m'minda).

2. KWA - tebulo maina.

3. NANGA - mkhalidwe umene kuyesa.

Onani kuti pamene chinenero SQL malembedwe si choncho-tcheru, mchitidwe wabwino kulemba mawu ndi mawu Otetezedwa (KUCHOKERA KUMENE KULI, etc.) mu zilembo zikuluzikulu, ndipo maina a matebulo ndi mizati - yaing'ono. SELECT приведен на рисунке ниже. Mophweka kwambiri chitsanzo cha ntchito MySQL woyendetsa sankhani kuchokera Sankhani pansipa.

An asterisk pambuyo mawu Sankhani ndi analogue a nfundo yaikhulu ZONSE zikutanthauza kuti kuchokera tebulo anapatsidwa kusankha mizati onse. Ngati mukufuna yekha ena m'minda pa tebulo, iwo ayenera anasonyeza mu malo oyenerera, ankasiyana mipatuliro. N'chimodzimodzinso ndi mayina a magome - ngati kuposa wina, kulowa iwo onse ankasiyana mipatuliro.

Ntchito KUMENE

N'zachidziwikire kuti mwina koma zindikirani kuti Mwachitsanzo yapitayi, palibe nfundo yaikhulu KUMENE - ichi ndi chifukwa mu nkhani iyi ndi sitifunanso. mawu awa si chofunika, ndipo ngati ntchito optional mu kusankha, pali ambiri, koma pang'ono kenako. Ngati ndinu pambuyo dzina anawonjezera tebulo KUMENE ndi chikhalidwe chirichonse monga mtundu = 'galu', ndiye zotsatira akonzedwa apeza mzere umodzi wokha ndi Pet m'malo mwa Edison. Chithunzi m'munsimu limasonyeza chitsanzo. Musanyalanyaze mawu DONGOSOLO NDI, pano zilibe kanthu, ndipo tikambirana pang'ono.

Dziwani kuti pambuyo kumene n'zothekanso kulemba zinthu angapo, koma salinso ankasiyana mipatuliro. Chifukwa chaichi, inu kugwiritsa ntchito mawu monga NDI kapena OR. Izi zidalira pa mmene zinthu anu ayenera kukwaniritsa. Ngati muli ndi chidwi chifukwa komwe kumakwanitsa zinthu zonse musankhe, ndiye pakati pa iwo ayenera kukhala NDI, ngati zotsatira ayenera kukwaniritsa mmodzi wa iwo, ndiye ntchito OR.

DONGOSOLO NDI mzera

Tanena kale kuti kuwonjezera pa KUMENE mu mawu Sankhani pali ambiri mfundo zina mungathe kusintha chifukwa ngati chofunika pa nkhani ina. Mmodzi mwa anthu amenewo "mfungulo" ndi dongosolo, ndi. Iwo amalola kuti mtundu zotsatira za chitsanzo mwa munda yeniyeni, onse akukwera ndi kutsikira. Ndi zokwanira mwachindunji monga ndime dzina pambuyo pake, malinga ndi mfundo imene mukufuna kuthetsa deta. Nkofunika mogwirizana ndi zinthu zingapo: choyamba - dzina kutchulidwa mawu akuti DONGOSOLO NDI, ndipo ayenera kupezeka mu Sankhani; chachiwiri - DONGOSOLO NDI ayenera kuyikidwa pa mapeto a pempho.

mtundu kusakhulupirika ndi kukwera (ASC), koma ngati mukufuna kuthetsa zotsatira mu ukutsika dongosolo, kulemba dzina munda m'malo ASC nfundo yaikhulu DESC.

Pomaliza

Takambirana chachikulu, koma osati onse a zida woyendetsa MySQL muzisankha. Sankhani kusiya kwa zochulidwa pamwamba, ali zambiri zochitika zina zimene kulola kuti akatenge kafukufuku Nawonso achichepere, flexibly Cofunika.