多條件查詢（and | or）?

mysql> SELECT * FROM pet WHERE species = 'dog' AND sex = 'f'; +‐‐‐‐‐‐‐+‐‐‐‐‐‐‐‐+‐‐‐‐‐‐‐‐‐+‐‐‐‐‐‐+‐‐‐‐‐‐‐‐‐‐‐‐+‐‐‐‐‐‐‐+ | name | owner | species | sex | birth | death | +‐‐‐‐‐‐‐+‐‐‐‐‐‐‐‐+‐‐‐‐‐‐‐‐‐+‐‐‐‐‐‐+‐‐‐‐‐‐‐‐‐‐‐‐+‐‐‐‐‐‐‐+ | Buffy | Harold | dog | f | 1989‐05‐13 | NULL | +‐‐‐‐‐‐‐+‐‐‐‐‐‐‐‐+‐‐‐‐‐‐‐‐‐+‐‐‐‐‐‐+‐‐‐‐‐‐‐‐‐‐‐‐+‐‐‐‐‐‐‐+ mysql> SELECT * FROM pet WHERE species = 'snake' OR species = 'bird'; +‐‐‐‐‐‐‐‐‐‐+‐‐‐‐‐‐‐+‐‐‐‐‐‐‐‐‐+‐‐‐‐‐‐+‐‐‐‐‐‐‐‐‐‐‐‐+‐‐‐‐‐‐‐+ | name | owner | species | sex | birth | death | +‐‐‐‐‐‐‐‐‐‐+‐‐‐‐‐‐‐+‐‐‐‐‐‐‐‐‐+‐‐‐‐‐‐+‐‐‐‐‐‐‐‐‐‐‐‐+‐‐‐‐‐‐‐+ | Chirpy | Gwen | bird | f | 1998‐09‐11 | NULL | | Whistler | Gwen | bird | NULL | 1997‐12‐09 | NULL | | Slim | Benny | snake | m | 1996‐04‐29 | NULL | +‐‐‐‐‐‐‐‐‐‐+‐‐‐‐‐‐‐+‐‐‐‐‐‐‐‐‐+‐‐‐‐‐‐+‐‐‐‐‐‐‐‐‐‐‐‐+‐‐‐‐‐‐‐+

優先執行括號中的邏輯

mysql> SELECT * FROM pet WHERE (species = 'cat' AND sex = 'm') ‐> OR (species = 'dog' AND sex = 'f'); +‐‐‐‐‐‐‐+‐‐‐‐‐‐‐‐+‐‐‐‐‐‐‐‐‐+‐‐‐‐‐‐+‐‐‐‐‐‐‐‐‐‐‐‐+‐‐‐‐‐‐‐+ | name | owner | species | sex | birth | death | +‐‐‐‐‐‐‐+‐‐‐‐‐‐‐‐+‐‐‐‐‐‐‐‐‐+‐‐‐‐‐‐+‐‐‐‐‐‐‐‐‐‐‐‐+‐‐‐‐‐‐‐+ | Claws | Gwen | cat | m | 1994‐03‐17 | NULL | | Buffy | Harold | dog | f | 1989‐05‐13 | NULL | +‐‐‐‐‐‐‐+‐‐‐‐‐‐‐‐+‐‐‐‐‐‐‐‐‐+‐‐‐‐‐‐+‐‐‐‐‐‐‐‐‐‐‐‐+‐‐‐‐‐‐‐+

檢索特定的列

mysql> SELECT name, birth FROM pet; +‐‐‐‐‐‐‐‐‐‐+‐‐‐‐‐‐‐‐‐‐‐‐+ | name | birth | +‐‐‐‐‐‐‐‐‐‐+‐‐‐‐‐‐‐‐‐‐‐‐+ | Fluffy | 1993‐02‐04 | | Claws | 1994‐03‐17 | | Buffy | 1989‐05‐13 | | Fang | 1990‐08‐27 | | Bowser | 1989‐08‐31 | | Chirpy | 1998‐09‐11 | | Whistler | 1997‐12‐09 | | Slim | 1996‐04‐29 | | Puffball | 1999‐03‐30 | +‐‐‐‐‐‐‐‐‐‐+‐‐‐‐‐‐‐‐‐‐‐‐+

查詢不重復的字段要使用關鍵詞DISTINCT?

mysql> SELECT DISTINCT owner FROM pet; +‐‐‐‐‐‐‐‐+ | owner | +‐‐‐‐‐‐‐‐+ | Benny | | Diane | | Gwen | | Harold | +‐‐‐‐‐‐‐‐+

可以使用組合條件查詢特定的列

mysql> SELECT name, species, birth FROM pet ‐> WHERE species = 'dog' OR species = 'cat'; +‐‐‐‐‐‐‐‐+‐‐‐‐‐‐‐‐‐+‐‐‐‐‐‐‐‐‐‐‐‐+ | name | species | birth | +‐‐‐‐‐‐‐‐+‐‐‐‐‐‐‐‐‐+‐‐‐‐‐‐‐‐‐‐‐‐+ | Fluffy | cat | 1993‐02‐04 | | Claws | cat | 1994‐03‐17 | | Buffy | dog | 1989‐05‐13 | | Fang | dog | 1990‐08‐27 | | Bowser | dog | 1989‐08‐31 | +‐‐‐‐‐‐‐‐+‐‐‐‐‐‐‐‐‐+‐‐‐‐‐‐‐‐‐‐‐‐+

?

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