查询包含字符‘e’的信息

% 代表不确定个数的字符（零个或多个）

SELECT employee_id, first_name
FROM employees
WHERE first_name LIKE '%e%';

 查询以字符‘e’开头的字符

SELECT employee_id, first_name
FROM employees
WHERE first_name LIKE 'e%';

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_  代表一个不确定的字符

查询第三个字符是‘e’的信息

SELECT employee_id, first_name
FROM employees
WHERE first_name LIKE '__e%';

查询第二个字符是‘_’，第三个字符是‘e’的信息：使用转义字符

SELECT employee_id, first_name
FROM employees
WHERE first_name LIKE '_\_e%';

ESCAPE指定一个字符代替‘\’

SELECT employee_id, first_name
FROM employees
WHERE first_name LIKE '_$_e%' ESCAPE '$';