1、查詢所有字段
SELECT * FROM t_student;
2流炕、查詢指定字段
SELECT stuName,gradeName FROM t_student;
3、Where條件查詢
SELECT * FROM t_student WHERE id=1;
SELECT * FROM t_student WHERE age>22;
4、帶IN關(guān)鍵字查詢
SELECT * FROM t_student WHERE age IN (21,23);
SELECT * FROM t_student WHERE age NOT IN (21,23);
5顽决、帶BETWEEN AND的范圍查詢
SELECT * FROM t_student WHERE age BETWEEN 21 AND 24;
SELECT * FROM t_student WHERE age NOT BETWEEN 21 AND 24;
6、帶LIKE的模糊查詢
“%”代表任意字符导匣；
“_” 代表單個字符才菠；
SELECT * FROM t_student WHERE stuName LIKE '張三'; 張三
SELECT * FROM t_student WHERE stuName LIKE '張三%';張三，張三X, 張三XX
SELECT * FROM t_student WHERE stuName LIKE '張三__'; 張三X
SELECT * FROM t_student WHERE stuName LIKE '%張三%'; 只要有張三的
7贡定、空值查詢
SELECT * FROM t_student WHERE sex IS NULL;
SELECT * FROM t_student WHERE sex IS NOT NULL;
8赋访、帶AND的多條件查詢
SELECT * FROM t_student WHERE gradeName='一年級' AND age=23
9、帶OR的多條件查詢
SELECT * FROM t_student WHERE gradeName='一年級' OR age=23
10缓待、DISTINCT去重復查詢
SELECT DISTINCT gradeName FROM t_student;
11蚓耽、對查詢結(jié)果排序
SELECT * FROM t_student ORDER BY age ASC;
SELECT * FROM t_student ORDER BY age DESC;
12、GROUP BY分組查詢
GROUP BY屬性名[HAVING條件表達式][WITH ROLLUP]
（1）單獨使用(毫無意義)旋炒；
SELECT * FROM t_student GROUP BY gradeName;? false?
（2）與GROUP_CONCAT()函數(shù)一起使用步悠；
SELECT gradeName,GROUP_CONCAT(stuName) FROM t_student GROUP BY gradeName;
（3）與聚合函數(shù)一起使用；
SELECT gradeName,COUNT(stuName) FROM t_student GROUP BY gradeName;
（4）與HAVING一起使用(限制輸出的結(jié)果)瘫镇；
SELECT gradeName,COUNT(stuName) FROM t_student GROUP BY gradeName HAVING COUNT(stuName)>3;
（5）與WITH ROLLUP一起使用(最后加入一個總和行)鼎兽；
SELECT gradeName,COUNT(stuName) FROM t_student GROUP BY gradeName WITH ROLLUP;
SELECT gradeName,GROUP_CONCAT(stuName) FROM t_student GROUP BY gradeName WITH ROLLUP;
13、LIMIT分頁查詢
LIMIT初始位置汇四，記錄數(shù)接奈；
SELECT * FROM t_student LIMIT 0,5;
SELECT * FROM t_student LIMIT 5,5;
SELECT * FROM t_student LIMIT 10,5;
