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  • 使MySQL查询区分大小写的实现方法

    发布:mdxy-dxy 字体:[增加 减小] 类型:转载

    我们在MySQL中使用SELECT语句查询时,可不可以使查询区分大小写?今天从网络上找到了方法,现总结如下。
     

    1、一种方法是可以设置表或行的collation,使其为binary或case sensitive。在MySQL中,对于Column Collate其约定的命名方法如下:

    *_bin: 表示的是binary case sensitive collation,也就是说是区分大小写的
    *_cs: case sensitive collation,区分大小写
    *_ci: case insensitive collation,不区分大小写


    ###########
    # Start binary collation example
    ###########
    mysql> create table case_bin_test (word VARCHAR(10)) CHARACTER SET latin1 COLLATE latin1_bin;
    Query OK, 0 rows affected (0.02 sec)

    mysql> INSERT INTO case_bin_test VALUES ('Frank'),('Google'),('froogle'),('flickr'),('FlicKr');
    Query OK, 5 rows affected (0.00 sec)
    Records: 5 Duplicates: 0 Warnings: 0

    mysql> SELECT * FROM case_bin_test WHERE word LIKE 'f%';
    +---------+
    | word |
    +---------+
    | froogle |
    | flickr |
    +---------+
    2 rows in set (0.00 sec)

    mysql> SELECT * FROM case_bin_test WHERE word LIKE 'F%';
    +---------+
    | word |
    +---------+
    | Frank |
    | FlicKr |
    +---------+
    4 rows in set (0.00 sec)

    ###########
    # End
    ###########

    2、另外一种方法

    ###########
    # Start case sensitive collation example
    ###########

    mysql> create table case_cs_test (word VARCHAR(10)) CHARACTER SET latin1 COLLATE latin1_general_cs;
    Query OK, 0 rows affected (0.08 sec)

    mysql> INSERT INTO case_cs_test VALUES ('Frank'),('Google'),('froogle'),('flickr'),('FlicKr');
    Query OK, 5 rows affected (0.00 sec)
    Records: 5 Duplicates: 0 Warnings: 0

    mysql> SELECT * FROM case_cs_test WHERE word LIKE 'F%';
    +---------+
    | word |
    +---------+
    | Frank |
    | FlicKr |
    +---------+
    4 rows in set (0.00 sec)

    mysql> SELECT * FROM case_cs_test WHERE word LIKE 'f%';
    +---------+
    | word |
    +---------+
    | froogle |
    | flickr |
    +---------+
    2 rows in set (0.00 sec)

    ###########
    # end
    ###########


    3、还有一种方法就是在查询时指定collation

    mysql> create table case_test (word VARCHAR(10)) CHARACTER SET latin1;
    Query OK, 0 rows affected (0.01 sec)

    mysql> INSERT INTO case_test VALUES ('Frank'),('Google'),('froogle'),('flickr'),('FlicKr');
    Query OK, 7 rows affected (0.01 sec)
    Records: 7 Duplicates: 0 Warnings: 0
    mysql> SELECT * FROM case_test WHERE word LIKE 'f%';
    +---------+
    | word |
    +---------+
    | Frank |
    | froogle |
    | flickr |
    | FlicKr |
    +---------+
    6 rows in set (0.01 sec)

    mysql> SELECT * FROM case_test WHERE word LIKE 'F%';
    +---------+
    | word |
    +---------+
    | Frank |
    | froogle |
    | flickr |
    | FlicKr |
    +---------+
    6 rows in set (0.01 sec)


    mysql> SELECT * FROM case_test WHERE word COLLATE latin1_bin LIKE 'F%';
    +---------+
    | word |
    +---------+
    | Frank |
    | FlicKr |
    +---------+
    4 rows in set (0.05 sec)

    mysql> SELECT * FROM case_test WHERE word COLLATE latin1_bin LIKE 'f%';
    +---------+
    | word |
    +---------+
    | froogle |
    | flickr |
    +---------+
    2 rows in set (0.00 sec)



    mysql> SELECT * FROM case_test WHERE word LIKE 'f%' COLLATE latin1_bin;
    +---------+
    | word |
    +---------+
    | froogle |
    | flickr |
    +---------+
    2 rows in set (0.00 sec)

    mysql> SELECT * FROM case_test WHERE word LIKE 'F%' COLLATE latin1_bin;
    +---------+
    | word |
    +---------+
    | Frank |
    | FlicKr |
    +---------+
    4 rows in set (0.01 sec)


    mysql> SELECT * FROM case_test WHERE word LIKE 'F%' COLLATE latin1_general_cs;
    +---------+
    | word |
    +---------+
    | Frank |
    | FlicKr |
    +---------+
    4 rows in set (0.04 sec)

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  • 原文地址:https://www.cnblogs.com/ldms/p/3431485.html
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