MySQL? ???? ?? ???? ???? ? ???? ??
??? ??????? ??? ? ?? ???? ???? ???? ?? ??? ????. ??? ????. ? ??? MySQL?? 3?? JOIN? ???? ?? ???? ??? ?????.
??: ? ?? ?? ???(??, ?? ? ???)? ?? ???? ?? ???? ? ???? ????. ????).
?? ???:
people id last_name first_name email 1 Smith Fred Fred@.. 2 Jones Tom Tom@.. 3 Doe Jane Jane@.. taxonomy id taxonomy 1 age 2 gender 3 height details id person_id detail_id content 1 1 1 36 2 1 2 M 3 1 3 5'10" 4 2 1 29 5 2 2 M 6 2 3 6'3" 7 3 1 27 8 3 2 F 9 3 3 5'8"
??? ??(? ???):
id last_name first_name email age 1 Smith Fred Fred@.. 36 2 Jones Tom Tom@.. 29 3 Doe Jane Jane@.. 27
3?? JOIN? ???? ???:
? ???? ???? ??? ???? ???. ?? ?? ???? ? ?? ?? ???? ???? 3?? JOIN:
CREATE TABLE new_table AS SELECT p.*, d.content AS age FROM people AS p JOIN details AS d ON d.person_id = p.id JOIN taxonomy AS t ON t.id = d.detail_id WHERE t.taxonomy = 'age';
? JOIN? people ???? ???? person_id ?? ???? ? ?? ?? ???? ??? ?? ?? ?? ???? ??? ?????. Detail_id ?? ???? ?? ?? ???? ???? ??? 'age'? ?? ??????.
?? ?? ??(?? ??? ??):
???? ????? ?? ??(??, ??, ? ?)? ????? ? ??? ?? ??? JOIN? ???? ???.
CREATE TABLE new_table AS SELECT p.*, d1.content AS age, d2.content AS gender, d3.content AS height FROM people AS p JOIN details AS d1 ON d1.person_id = p.id JOIN taxonomy AS t1 ON t1.id = d1.detail_id JOIN details AS d2 ON d2.person_id = p.id JOIN taxonomy AS t2 ON t2.id = d2.detail_id JOIN details AS d3 ON d3.person_id = p.id JOIN taxonomy AS t3 ON t3.id = d3.detail_id WHERE t1.taxonomy = 'age' AND t2.taxonomy = 'gender' AND t3.taxonomy = 'height';
? ?? ??? ???? ?? ?? ???? ?? ?? ?? ???? ? ???? ??? ? ????.
? ??? JOIN? ???? ? ?? MySQL ???? ???? ? ???? ???? ??? ??????? ?? ?????. ??? ??? PHP ??? ????? ?? ?? ??? ?????!
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