Mysql easy to solve problems in the case

The following article mainly introduces Mysql case-sensitive solution to some of the problems, this article is through Mysql sensitivity to its detailed study, the following is the article on the specific content of a detailed introduction, hope you browse after Mysql case-related issues have a better understanding.

1, database and table name

In Mysql, the database and table correspond to the directories and files in those directories, so the inherent operating system sensitivity determines the case sensitivity of the database and table naming. This means that database and table names are case-sensitive on Unix and case-insensitive on Win32.

Note: On Win32, you should not reference a given database or table in a different case in the same query, even though the database and table names ignore Mysql case. The following query will not work because it references a table as my_table and as MY_TABLE:

1.Mysql> SELECT * FROM my_table WHERE MY_TABLE.col = 1;

2, the column name

Column names are case-insensitive in all cases.

3, the table's alias

The alias of the table is case sensitive. The following query will not work:: Because it references aliases with a and A:

1.Mysql> SELECT col_name FROM tbl_name AS a

2. WHERE a.col_name = 1 OR A.col_name = 2;

4, column alias

Alias ​​column is ignored case.

5, string comparison and pattern matching

By default, Mysql searches are case insensitive (although there are some character sets that never ignore Mysql, such as Czech). This means that if you search with col_name LIKE a% you will get all the column values ​​starting with A or a. If you want to make the search case sensitive, check for a prefix like INDEX (col_name, "A") = 0. Or STRCMP (col_name, "A") = 0 if the column value must be exactly "A".

Simple comparison operations (> =,>, =, <, <=, sorting, and aggregation) are based on the "sorted value" of each character. Characters that have the same ordering value (like E, e) are treated as the same character!

The LIKE comparison is performed on the uppercase value of each character ("E" = "e").

If you want a column to always be treated as a case-sensitive Mysql, declare it BINARY.

E.g:

1.Mysql> SELECT "E" = "e", "E" = BINARY "e";

2. + --------- + ---------------- + | "E" = "e" | "E" = BINARY "e"

| + --------- + ---------------- + | 1 | 0 | + --------- + ----- ----------- +

The relevant content is the description of Mysql case, I hope it will give you some help in this regard.