實訓(xùn)案例名稱：基本查詢語法一、任務(wù)介紹MySQL使用關(guān)鍵字SELECT來進(jìn)行查詢。實現(xiàn)步驟1.查詢數(shù)據(jù)#使用用戶名root和相應(yīng)密碼，連接本地MySQLC:\Users\Administrator>mysql-uroot-p123456mysql:[Warning]Usingapasswordonthecommandlineinterfacecanbeinsecure.#使用shop數(shù)據(jù)庫mysql>USEshop;Databasechanged#查詢用戶表user中的數(shù)據(jù)，顯示所有字段的數(shù)據(jù)mysql>SELECT*FROMuser;+----+-------+------+------+----------+|id

|name

|sex

|age

|password

|+----+-------+------+------+----------+|3|david

|女|28|111111

||4|小紅

|女|27|123456

||5|小明

|男|10|123456

||6|小剛

|男|12|123456

||7|小王

|男|14|111111

||8|小綠

|女|34|222222

||9|曉峰

|男|15|333333

||10|小影

|女|26|444444

||11|大梅

|女|27|555555

|+----+-------+------+------+----------+9rowsinset(0.00sec)#查詢用戶表user中的數(shù)據(jù)，只顯示name字段的數(shù)據(jù)mysql>SELECTnameFROMuser;+-------+|name

|+-------+|david||小紅||小明||小剛||小王||小綠||曉峰||小影||大梅|+-------+9rowsinset(0.00sec)#按條件進(jìn)行查詢，查詢性別為男的數(shù)據(jù)mysql>SELECT*FROMuserWHEREsex='男';+----+------+------+------+----------+|id|name|sex

|age|password

|+----+------+------+------+----------+|5|小明|男

|10|123456

||6|小剛|男

|12|123456

||7|小王|男

|14|111111

||9|曉峰|男

|15|333333

|+----+------+------+------+----------+4rowsinset(0.00sec)#查詢年齡大于20的數(shù)據(jù)mysql>SELECT*FROMuserWHEREage>20;+----+-------+------+------+----------+|id|name

|sex|age|password

|+----+-------+------+------+----------+|3

|david

|女|28|111111||4

|小紅

|女|27|123456||8

|小綠

|女|34|222222||10|小影

|女|26|444444||11

|大梅

|女|27|555555|+----+-------+------+------+----------+5rowsinset(0.00sec)#查詢總共有多少條記錄mysql>SELECTcount(*)FROMuser;+----------+|count(*)|+----------+|9|+----------+1rowinset(0.08sec)#查詢年齡總和mysql>SELECTsum(age)FROMuser;+----------+|sum(age)|+----------+|193|+----------+1rowinset(0.05sec)#查詢年齡最大的數(shù)據(jù)mysql>SELECTmax(age)FROMuser;+----------+|max(age)|+----------+|34

|+----------+1rowinset(0.04sec)#按性別進(jìn)行分組查詢mysql>SELECTsex,count(*)FROMuserGROUPBYsex;+------+----------+|sex

|count(*)

|+------+----------+|女|5

||男|4

|+------+----------+2rowsinset(0.01sec)#按年齡降序排列查詢結(jié)果mysql>SELECT*FROMuserORDERBYageDESC;+----+-------+------+------+----------+|id|name|sex|age|password|+----+-------+------+------+----------+|8 |小綠 |女|34|222222||3 |david |女|28|111111||4 |小紅 |女|27|123456||11 |大梅 |女|27|555555||10 |小影 |女|26|444444||9 |曉峰 |男|15|333333||7 |小王 |男|14|111111||6 |小剛 |男|12|123456||5 |小明 |男|10|123456|+----+-------+------+------+----------+9rowsinset(0.00sec)#按年齡升序排列查詢結(jié)果mysql>SELECT*FROMuserORDERBYageASC;+----+-------+------+------+----------+|id|name

|sex

|age

|password|+----+-------+------+------+----------+|5 |小明

|男|10|123456||6 |小剛

|男|12|123456||7 |小王

|男|14|111111||9 |曉峰

|男|15|333333||10 |小影

|女|26|444444||4 |小紅

|女|27|123456||11 |大梅

|女|27|555555||3 |david

|女|28|111111||8 |小綠

|女|34|222222|+----+-------+------+------+----------+9rowsinset(0.00sec)#查詢前5條記錄mysql>SELECT*FROMuserLIMIT0,5;+----+-------+------+------+----------+|id|name|sex

|age|password

|+----+-------+------+------+----------+|3|david

|女|28|111111

||4|小紅|女|27