建立一個學生表，插入10條資料CREATE TABLE student (id int, name varchar(20), score integer);
INSERT INTO student VALUES (1, 'jack', 90);
INSERT INTO student VALUES (2, 'tom', 85);
INSERT INTO student VALUES (3, 'allen', 79);
INSERT INTO student VALUES (4, 'michael', 95);
INSERT INTO student VALUES (5, 'steven', 65);
INSERT INTO student VALUES (6, 'kevin', 100);
INSERT INTO student VALUES (7, 'kate', 60);
INSERT INTO student VALUES (8, 'david', 55);
INSERT INTO student VALUES (9, 'kelly', 95);
INSERT INTO student VALUES (10, 'bale', 99);
查詢分數小于80分的學生，顯示row_numberSELECT @curRow := @curRow + 1 AS row_num,
s.id,
s.name,
s.score
FROM student s
JOIN (SELECT @curRow := 0) r
WHERE s.score < 80;
