In mysql, if I use common data sorting methods, we may not get the expected results, but mysql provides us with the CAST CONVERT function, which can CONVERT numbers accordingly, I used this function to sort Chinese characters in the past.
Let's
Simple to say about MySQL's varchar sorting problem, a cautionary tale.
Sample Table structure:
Let's take a look at my table structure
code is as follows
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Show create table Cardserver G **************
Mysql varchar sorting CAST, CONVERT function type conversion, varcharconvert
When creating a table on your own, you should create a field type as varchar (2). In fact, it should be set as integer (2). But today, we found a Sorting Problem in the
When you build the table, a field type is created as varchar (2), in fact, it should be built as an integer (2), but today in the background to find the problem of sorting, varchar sort has a problem, so how to solve it?Example table structure:
First Reader Network reference
The code is as follows
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CONVERT (expr USING transcoding_name)
In MySQL, transcoding names are the same as the corresponding character set names.
Examples:
MySQL provides us with two types of conversion functions: cast and convert, how can we let go of the ready-made stuff?1 BINARY[(N)]2 CHAR[(N)]3 DATE4 DATETIME5 DECIMAL6Signed[INTEGER]7 Time8UNSIGNED[INTEGER]Example:--use cast to convert varchar to
MySQL database converts int to varchar for slow query, mysqlvarchar
Two slow queries are processed in the last week because the int type cannot be converted to varchar.
CREATE TABLE `appstat_day_prototype_201305` (`day_key` date NOT NULL DEFAULT '190
Today, when parsing dedecms, the MySQL time field found in Deder is usedint (notNULLDEFAULT'0';Then found this article on the Internet, it seems that if the time field has to participate in the operation, with int better, one does not have to
When parsing DEDECMS today, we found that the MYSQL time fields of deder use the INT type, and then we found this article online. it seems that if the time field is involved in the calculation, it would be better to use the int type, first, you do
Is today in the background to find a sort of problem. So, there's no way to change it. Here is a brief look at MySQL varchar sorting problem, warning.
Sample Table structure:Let's take a look at my table structure
The code is as follows
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