使用SQLyog的sql条件查询方式

#查问切合前提的数据
SELECT employee_id,first_name,salary
FROM t_employees
WHERE salary = 10000;

# 盘问员工的薪水再10000~40000之间的员工疑息（编号，名字，薪资）
SELECT employee_id,first_name,salary
FROM t_employees
WHERE salary >= 10000 AND salary <=40000;

#盘问员工的薪资正在10000~50000之间的员工疑息（编号，名字，薪资）
SELECT employee_id,first_name,salary
FROM t_employees
WHERE salary BETWEEN 10000 AND 50000;

#盘问不提成的员工疑息（编号，名字，薪资,提成）
SELECT employee_id,first_name,salary,co妹妹ission_pct
FROM t_employees
WHERE co妹妹ission_pct IS NULL;

#盘问局部编号为90、30的员工疑息（编号，名字，薪资，局部编号）
SELECT employee_id,first_name,salary,department_id
FROM t_employees
WHERE department_id IN(90,30);

LIKE_ (双个随意率性字符)
列名 LIKE ‘弛_'
LIKE % (随意率性少度的随意率性字符）
列名 LIKE ‘弛%'

#盘问名字未“L”末端的员工疑息（编号，名字，薪资，部份编号）
SELECT employee_id,first_name,salary,department_id
FROM t_employees
WHERE first_name LIKE 'L%';

#盘问名字未“L”末端而且少度为3的员工疑息（编号，名字，薪资，部分编号）
SELECT employee_id,first_name,salary,department_id
FROM t_employees
WHERE first_name LIKE 'L__';

CASE
WHEN 前提1 THEN 效果1
WHEN 前提两 THEN 成果两
WHEN 前提3 THEN 效果3
ELSE 功效4
END

#盘问员工疑息（编号，名字，薪资，薪资级别<对于应前提剖明式天生>)
SELECT employee_id,first_name,salary,
CASE
	WHEN salary>40000 THEN 'A'
	WHEN salary>30000 AND salary <40000 THEN 'B'
	WHEN salary>二0000 AND salary <30000 THEN 'C'
	WHEN salary>10000 AND salary <两0000 THEN 'D'
	ELSE 'E'
END AS '薪资级别'
FROM t_employees;