LIKE 操作符用于在 WHERE 子句中搜索列中的指定模式。
语法：
SELECT column_name(s) FROM table_name WHERE column_name LIKE pattern
pattern这里就是放指定模板的地方，而这里就要用到“ % ”，也叫做通配符
%如果是放在条件前面，那就是查以...结尾的数据；例如：%李
%如果是放在条件后面，那就是查以...开头的数据；例如：李%
%如果是在条件前后都存在，那就是查包含的数据；例如：%李%
小知识点：
error 1064 (42000): you have an error in your sql syntax; check the manual that corresponds to your mysql server version for the right syntax to use near "%z" at line 1
1064的错误就是LIKE查询时(语法错误)，通配符处没加引号，所以才会报错...
正确展示例如："%李%"
示例1：终端运行sql且WHERE子句中使用LIKE
查询地址以Hang开头的人员信息
root@7c6316b19d80:/# mysql -u root -p Enter password: Welcome to the MySQL monitor. Commands end with ; or g. Your MySQL connection id is 140 Server version: 5.6.51 MySQL Community Server (GPL) mysql> mysql> select * from test_user where address like "Hang%"; +----+--------+-------------+----------+ | id | name | mobile | address | +----+--------+-------------+----------+ | 3 | python | 18856565858 | Hangzhou | | 4 | java | 17756565858 | Hangzhou | | 5 | php | 15556565858 | Hangzhou | | 6 | c# | 17748484142 | Hangzhou | +----+--------+-------------+----------+ 4 rows in set (0.00 sec) mysql>
查询地址以u结尾的人员信息
mysql> select * from test_user where address like "%u"; +----+--------+-------------+----------+ | id | name | mobile | address | +----+--------+-------------+----------+ | 3 | python | 18856565858 | Hangzhou | | 4 | java | 17756565858 | Hangzhou | | 5 | php | 15556565858 | Hangzhou | | 6 | c# | 17748484142 | Hangzhou | +----+--------+-------------+----------+ 4 rows in set (0.00 sec) mysql>
示例2：使用python脚本执行含LIKE的sql语句
查询地址包含z字符的人员信息
import pymysql
# 连接数据库
connection = pymysql.connect(host="localhost", user="root", password="123456",
database="testing", port=3306, charset="utf8",
cursorclass=pymysql.cursors.DictCursor)
try:
with connection:
with connection.cursor() as cursor:
sql = """
SELECT
*
FROM
test_user
WHERE
address LIKE "%z%";
"""
cursor.execute(sql)
result = cursor.fetchall()
for i in result:
print(i)
except pymysql.err.MySQLError as _error:
raise _error{"id": 3, "name": "python", "mobile": "18856565858", "address": "Hangzhou"}
{"id": 4, "name": "java", "mobile": "17756565858", "address": "Hangzhou"}
{"id": 5, "name": "php", "mobile": "15556565858", "address": "Hangzhou"}
{"id": 6, "name": "c#", "mobile": "17748484142", "address": "Hangzhou"}
Process finished with exit code 0查询地址不包含z字符的人员信息
try:
with connection:
with connection.cursor() as cursor:
sql = """
SELECT
*
FROM
test_user
WHERE
address NOT LIKE "%z%";
"""
cursor.execute(sql)
result = cursor.fetchall()
for i in result:
print(i)
except pymysql.err.MySQLError as _error:
raise _error{"id": 1, "name": "张三三", "mobile": "17748484141", "address": "浙江杭州"}
{"id": 9, "name": "111", "mobile": "18847474549", "address": "浙江杭州"}
Process finished with exit code 0知识点扩展：python中的mysql数据库like模糊查询
%在python中是个特殊的符号，如%s，%d分别代表了字符串占位符和数字占位符。
大家知道，mysql的模糊查询也需要用到%。
所以，可以先把需要查的字符串抽出来，再以参数方式传入。
args = "%"+subtitle+"%" sqlQueryTitle="select count(*) from tbl_peng_article where title like "%s""%args
