(uint) sql_field->length); 关于`calc_pack_length` 的计算方式如下: size_t calc_pack_length(enum_field_types type, size_t length) { switch (type) { case MYSQL_TYPE_VAR_STRING: case MYSQL_TYPE_STRING: case MYSQL_TYPE_DECIMAL: return (length); case MYSQL_TYPE_VARCHAR: return (length +...
length=field->pack_length; /* 这个pack_length就是和字段类型相关,以varchar为例*/ /* sql/sql_table.cc:3082 */ sql_field->sql_type= MYSQL_TYPE_VAR_STRING; sql_field->pack_length= calc_pack_length(sql_field->sql_type, (uint) sql_field->length); 关于`calc_pack_length` 的计算方式如下...
因此了解一下reclength的计算过程:1./* sql/unireg.cc:843 */ 2.if (field->offset + data_offset + length > reclength) 3.reclength= field->offset + data_offset + length; 4. 5./* 6.field->offset 的计算方式 7.sql/sql_table.cc:3816 8.*/ 9.while ((sql_field=it++)...
Field 1: `i` Catalog: `def` Database: `test` Table: `sample` Org_table: `sample` Type: LONG Collation: binary (63) Length: 3 Max_length: 7 Decimals: 0 Flags: NUM 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 在这种情况下,如果客户端傻乎乎地按照Length的值分配内存,必将Buffe...
length 的计算方式 sql/unireg.cc:833 */ length=field->pack_length; /* 这个pack_length就是和字段类型相关,以varchar为例*/ /* sql/sql_table.cc:3082 */ sql_field->sql_type= MYSQL_TYPE_VAR_STRING; sql_field->pack_length= calc_pack_length(sql_field->sql_type, ...
Field NameData Type id BIGINT (20) title varchar(25) Description Text A query like: SELECT * FROM TEST ORDER BY description DESC; But I would like to order by the field size/length of the field description. The field type will be TEXT or BLOB. sql mysql sql-order-by Share Follow ...
MySQL常用数据类型 length 专题 MySQL-data_type数据类型 1、查看数据类型 mysql> help data type //通过help对数据进行查看,以及使用的方法 2、MySQL常见的数据类型 整数int、定点小数dec、浮点数float、字符串varchar、时间-时区、布尔bool、位 前言=== 在MySQL数据库中,进行数据存储时,难免会出现数据类型转换,...
uint32 pack_length () const final void sql_type (String &str) const final uint32 max_display_length () const final Field_long * clone (MEM_ROOT *mem_root) const final Makes a shallow copy of the Field object. More... uchar * pack (uchar *to, const uchar *from, size_t max_leng...
table_option: {AUTOEXTEND_SIZE [=] value| AUTO_INCREMENT [=] value| AVG_ROW_LENGTH [=] value| [DEFAULT] CHARACTER SET [=] charset_name| CHECKSUM [=] {0 | 1}| [DEFAULT] COLLATE [=] collation_name| COMMENT [=] ‘string’| COMPRESSION [=] {‘ZLIB’ | ‘LZ4’ | ‘NONE’}| ...
INSERT INTO table_name ( field1, field2,...fieldN ) VALUES ( value1, value2,...valueN ); 实例: INSERT INTO User(user_name,user_sex,insert_date) VALUES('admin','男','2023-08-29'); 插入数据行 9、查询数据行 语法 SELECT column_name,column_name ...