LIKE 操作符用于在 WHERE 子句中搜索列中的指定模式。
语法:
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SELECT column_name(s)
FROM table_name
WHERE column_name LIKE pattern
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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
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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>
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查询地址以u结尾的人员信息
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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>
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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
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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
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{ '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
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查询地址不包含z字符的人员信息
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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
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{ '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
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至此,使用LIKE操作符查询完毕...
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。
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args = '%' +subtitle+ '%'
sqlQueryTitle= "select count(*) from tbl_peng_article where title like '%s'" %args
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原文链接:https://blog.csdn.net/LIFENG0402/article/details/118369315