MySQL tīpako i tīpako: tīpako kaiwhakahaere

MySQL, rite tetahi atu pūnaha whakahaere pātengi raraunga tūhonohono, he i roto i tona hanganga te tauira tauākī Tīpakohia. Ko te kore e ofo tenei, no te mea i roto i nga pātengi raraunga ngā mōhiohio matatapu matua ki te tiki i te reira, no te tika. select from SELECT позволяет делать это множеством различных способов, предоставляя большой набор инструментов. MySQL tīpako i taea tauākī Tīpakohia ki a koutou te mahi i tenei i roto i te maha ngā huarahi rerekē, whakarato he huinga nui o taputapu.

tāuta MySQL

whakatinana MySQL te rite i raro i Windows, me raro Linux. Hei tāuta MySQL Ubuntu, te mahi kapa e rua tika i te tauranga o te OS:

- sudo pai-tiki tāuta mysql-tūmau.

- sudo pai-tiki tāuta mysql-kiritaki.

Hoki MySQL Windows, tika tiki i te pae mōhiohio "pātengi raraunga" pōkai tāutanga tika, me te rere ratou.

Ko te hanganga whānui o te tauākī Tīpakohia

Whakaotia hanganga i roto i te MySQL tīpako i tauākī Tīpakohia ko e whai ake:

1. Tīpakohia - ingoa tīwae (mara).

2. MAI - ripanga ingoa.

3. HEA - ki te huru i roto i nei te whāwhā.

Kia mōhio ai i te kore, ko te take-tairongo te wetereo reo SQL, he mahi pai ki te tuhituhi tauākī me kupumatua i rahuitia (FROM, HEA, me ētahi atu) i roto i reta nui, me nga ingoa o nga papa me tīwae - iti. SELECT приведен на рисунке ниже. Ko te tauira tino ohie o te whakamahi i MySQL operator tīpako i Tīpakohia whakaaturia ana i raro.

Whetūriki i muri i te kupu Tīpakohia ko te orotahi o te kupu matua tikanga KATOA e i te tepu i homai ki te tīpako tīwae katoa. Ki te hiahia i roto i te tahi mau anake o nga mara o te tepu koutou, kia tohua ratou i roto i te wahi e tika ana, wehea e ngā piko. Ko te taua pā ki te ingoa o te papa - ki te neke atu i te kotahi, tomo ratou wehea e ngā piko katoa.

Mā te whakamahi i te WHEA

Oia mau, e kore i taea e koutou te āwhina engari kite e i roto i te tauira mua, kahore he kupu matua HEA - ko tenei te mea i roto i tenei take ko reira kore matou e hiahia ana. e kore te tenei tauākī hiahiatia, me taua ngā kōwhiringa i roto i Tīpakohia, i reira e maha, engari ko ratou he iti bit muri. Ki te ko koe i muri i tāpiri te ingoa he tepu HEA me tetahi huru, pērā i te momo = 'kuri', na ka whiwhi i te huinga hua kotahi anake haupae ki te mōkai i runga i mo o Edison. E whakaatu ana te ahua i raro i te tauira. Kaua e Waiho te tauākī ORDER BY, konei e kore e mea faufaa te reira, a ka ka kōrero reira he iti i muri mai.

E tano ia tapao e muri i te hea, ko te hoki e taea ki te tuhituhi tikanga maha, engari kei te kore wehea e ngā piko. Hoki tenei whakaaro, whai koe ki te whakamahi i kupu pērā i AND RĀNEI ranei. Te reira i katoa tei runga i te āhua o te tikanga kia tutaki koutou tikanga. Ki te hiahia i roto i te hua e makona nga tikanga katoa whakapūtā koutou, ka waenganui i me kia ratou AND, ki te kia makona i te hua i te iti rawa tetahi o ratou, ka whakamahi i te RĀNEI koe.

ORDER BY rara

whakahuatia matou e i roto i te tua ki te HEA i roto i te tauākī Tīpakohia reira e maha atu kupumatua ki e taea e koe rāwekeweke i te hua whakaturia rite hiahiatia i roto i te āhuatanga ngā. Ko tētahi taua "mau taviri" he Tuhinga BY. āhei te reira ki a koutou te kōmaka te hua o te tauira i roto i te mara motuhake, e rua e piki ana, e heke. He mea nui ki te tautuhi tika i te ingoa tīwae muri ia ia, kia rite ki nga uara e hiahia ana koe ki te kōmaka te raraunga. He mea nui ki te ū ki te maha tikanga: ko te tuatahi - te ingoa i tohua i roto i te tauākī, ORDER BY, a me i kona i roto i te Tīpakohia; tuarua - ORDER BY me whakanohoia i te mutunga o te tono.

Kei te piki ana i te ahua taunoa (ASC), engari, ki te hiahia koe ki te kōmaka te hua i roto i te heke te raupapa, tuhituhi i muri i te ingoa mara hei utu o ASC kupu matua auheke.

mutunga

arotakehia matou te matua, engari e kore e katoa o te taputapu te kaiwhakahaere MySQL tīpako i. Tīpakohia, haunga te hunga whakahuatia i runga ake, kua he rota o te tahi atu āhuatanga e tukua ki te tiki raraunga i te pātengi raraunga, ngāwari me tōtika.