


PHP method to obtain the field name and detailed information of the mysql data table, mysql field
First we need to understand the SQL statements for querying MySQL database/table related information:
SHOW DATABASES //List MySQL Server databases.
SHOW TABLES [FROM db_name]
SHOW CREATE TABLES tbl_name //Export data table structure.
SHOW TABLE STATUS [FROM db_name] //List the data table and table status information.
SHOW COLUMNS FROM tbl_name [FROM db_name] //List data table fields
SHOW FIELDS FROM tbl_name [FROM db_name], DESCRIBE tbl_name [col_name].
SHOW FULL COLUMNS FROM tbl_name [FROM db_name]//List fields and details
SHOW FULL FIELDS FROM tbl_name [FROM db_name] //List complete field attributes
SHOW INDEX FROM tbl_name [FROM db_name] //List table indexes.
SHOW STATUS
SHOW VARIABLES
SHOW PROCESSLIST //List execution commands.
SHOW GRANTS FOR user //List a user’s permissions
As you can see from the above SQL statement, we can use SHOW FULL COLUMNS to list fields and detailed information. Sample code:
$rescolumns = mysql_query("SHOW FULL COLUMNS FROM ".TB_NAME."") ;
while($row = mysql_fetch_array($rescolumns)){
// echo 'Field name: '.$row['Field'].'-Data type: '.$row['Type'].'-Comment: '.$row['Comment'];
// echo '
';
print_r($row);
}
Print results:
Array ( [0] => id [Field] => id [1] => char(2) [Type] => char(2) [2] => utf8_general_ci [Collation] => utf8_general_ci [3] => NO [Null] => NO [4] => PRI [Key] => PRI [5] => [Default] => [6] => [Extra] = > [7] => select,insert,update,references [Privileges] => select,insert,update,references [8] => [Comment] => )
Array ( [0] => title [Field] => title [1] => char(50) [Type] => char(50) [2] => utf8_general_ci [Collation] = > utf8_general_ci [3] => YES [Null] => YES [4] => [Key] => [5] => [Default] => [6] => [Extra] => [7] => select,insert,update,references [Privileges] => select,insert,update,references [8] => Recommended storage: title, name and other information [Comment] => Recommendation Storage: title, name and other information)
Array ( [0] => des [Field] => des [1] => varchar(255) [Type] => varchar(255) [2] => utf8_general_ci [Collation] = > utf8_general_ci [3] => YES [Null] => YES [4] => [Key] => [5] => [Default] => [6] => [Extra] => [7] => select,insert,update,references [Privileges] => select,insert,update,references [8] => [Comment] => )
…………
Supplementary information:
Of course you can also use mysql_list_fields — to list the fields in the MySQL results. mysql_list_fields() obtains information about a given table name. The parameters are the database name and table name, and returns a result pointer.
However, the mysql_list_fields() function is deprecated. It is better to use mysql_query() to issue a SQL statement SHOW COLUMNS FROM table [LIKE 'name'] instead. For details, please refer to the PHP help documentation: PHP: mysql_list_fields - Manua
I did the test like this:
create table music(
id varchar(10),
title varchar(100),
name varchar(10)
);
insert into music values('2','farewell','12354');
insert into music values('15','friend','5454');
insert into music values('161 ','Farewell','4668');
$conn=mysql_connect("localhost:3307","Database username","Database password");
mysql_select_db("date");
$result=mysql_query("select max(id+0) max_id from music",$conn);
$field=mysql_fetch_row($result);
print_r($ field);
?>
Result: Array ( [0] => 161 )
Because max() cannot be used for varchar in mysql, the id type is converted by id+0 to solve this problem. If the id is an integer when you create the table, you can use max() directly. For detailed explanation, see: hb.qq.com/a/20110624/000061.htm.
mysql_query executes sql statements and show tables

php把负数转为正整数的方法:1、使用abs()函数将负数转为正数,使用intval()函数对正数取整,转为正整数,语法“intval(abs($number))”;2、利用“~”位运算符将负数取反加一,语法“~$number + 1”。

实现方法:1、使用“sleep(延迟秒数)”语句,可延迟执行函数若干秒;2、使用“time_nanosleep(延迟秒数,延迟纳秒数)”语句,可延迟执行函数若干秒和纳秒;3、使用“time_sleep_until(time()+7)”语句。

php除以100保留两位小数的方法:1、利用“/”运算符进行除法运算,语法“数值 / 100”;2、使用“number_format(除法结果, 2)”或“sprintf("%.2f",除法结果)”语句进行四舍五入的处理值,并保留两位小数。

判断方法:1、使用“strtotime("年-月-日")”语句将给定的年月日转换为时间戳格式;2、用“date("z",时间戳)+1”语句计算指定时间戳是一年的第几天。date()返回的天数是从0开始计算的,因此真实天数需要在此基础上加1。

php字符串有下标。在PHP中,下标不仅可以应用于数组和对象,还可应用于字符串,利用字符串的下标和中括号“[]”可以访问指定索引位置的字符,并对该字符进行读写,语法“字符串名[下标值]”;字符串的下标值(索引值)只能是整数类型,起始值为0。

方法:1、用“str_replace(" ","其他字符",$str)”语句,可将nbsp符替换为其他字符;2、用“preg_replace("/(\s|\ \;||\xc2\xa0)/","其他字符",$str)”语句。

在php中,可以使用substr()函数来读取字符串后几个字符,只需要将该函数的第二个参数设置为负值,第三个参数省略即可;语法为“substr(字符串,-n)”,表示读取从字符串结尾处向前数第n个字符开始,直到字符串结尾的全部字符。

php判断有没有小数点的方法:1、使用“strpos(数字字符串,'.')”语法,如果返回小数点在字符串中第一次出现的位置,则有小数点;2、使用“strrpos(数字字符串,'.')”语句,如果返回小数点在字符串中最后一次出现的位置,则有。


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