mysql field

MySQL field typeMySQL supports multiple types and can be broadly divided into three categories: numeric, date/time, and string (character) types.Numeric type type size Range (signed) Range (unsigned) Use

Order By field (VALUE,STR1,STR2,STR3.)Parameter description value is the field name, followed by the specified field value to sortEg: Sort by field degree education sizeSELECT * from Education_info where school= ' Peking University ' order by field (

Today, after a database migration to a project, there was an error with field ' xxx ' doesn ' t having a default value, and this error was never seen before the migration. Later, after the inquiry manual and other information, found that the error

Retrieve ID = 2 or id = 5 or id = 9 or id = or id = 38.Then according to 2, 5, 9, 56, 38 in this order, this is the topic requires the following for the solution: 1. SELECT * from ' test ' WHERE ' id ' in (2,5,9,56,38) the ORDER by FIELD (' id ', 2,5

1. Add primary key (primary key index):ALTER TABLE ' table_name ' ADD PRIMARY KEY (' column ')2. Add unique (unique index):ALTER TABLE ' table_name ' Add UNIQUE (' column ') 3. Add index (normal index): ALTER TABLE ' table_name ' Add index

When reading a field in a database, some fields may be read differently depending on the environment, and reading the field values in the SQL database is the most datatable.rows[row [column], but there are some differences in MySQL. In flex it can

============================================================phil-prod-20141212, field add "-00" =========It is necessary to modify the data of the online advance treasure data and the easy loan related problem data (batch)MongodbBindingloanNeed to

Will install MySQL, will be a few SQL statements, will JDBC, hibernate configuration, thought will be MySQL, in recent days the interview was asked to MySQL problem, shame, systematic study.One of the MySQL optimizations, select the appropriate

Most developers should have encountered the experience of storing a comma-separated string in the MySQL field, and this field should have several commonalities, regardless of whether the segmented field represents an ID or tag. The divided

How many word lengths can be accommodated in a row? How long can each field have? is the limit length of the data type fixed? With these questions, we began a series of studies.First, the length of the field that the row holdsAs is known to all,

MySQL field encryption and decryption 1. Encryption: Aes_encrypt (' admin ', ' key ') decryption: aes_decrypt (password, ' key ') 2. Bi-directional encryption is encrypted by a key, which is only known when the key is decrypted. People to

MySQL field type detailedOriginal: http://www.cnblogs.com/100thMountain/p/4692842.htmlMySQL supports a large number of column types, which can be divided into 3 categories: numeric types, date and time types, and string (character) types. This

MyBatis Special handling of the text type, within the selectbyexamplewithblobs, the criteria does not. But you can write it yourself in Exampler, and he will automatically map it to a SQL statement for querying.Query codeNew arraylist<>new

Excerpt from: http://zuo.ai.xiao.blog.163.com/blog/static/6079155320121293750732/1. Number TypeSigned unsigned storage (bytes)tinyint-128 to 127 0 to 255 1 = 2^8 (one byte equals 8 bit binary)smallint-32768 to 32767 0 to 65535 2mediumint-8388608 to 8

1. Questions:Wrote a registration page, the local server did not error, uploaded to the space after the problem occurs.Literally, a field is not set to a default value.Follow the prompts to find the SQL statement ' integral ' varchar (225) Not NULL,

Original: https://www.cnblogs.com/jennyyin/p/7895010.htmlNumeric type Type Size Range (signed) Range (unsigned) Use TINYINT 1 bytes (-128,127) (0,255) Small integer value

One: Field modifier1:null and NOT NULL modifiersLet's take a look at this example.Mysql> CREATE TABLE worker (ID int not null,name varchar (8) Not null,pass varchar (a) not null);Mysql> INSERT into worker values (1, ' HA ', ' 123456 ');Mysql> INSERT

CREATE TABLE ' comment ' (' c_id ' int (one) not NULL auto_increment COMMENT ' Comment ID ',' u_id ' int (one) not NULL COMMENT ' user ID ',' Name ' varchar (not NULL default ' COMMENT ' user name '),' Content ' varchar (+) not NULL default '

1. Tinyint: Only 128 to 127 of the size of the number, do not care about the following definition, such as tinyint (9). Requires 1 bytes of storage space. When unsigned is added, the number can be increased from 0 to 255 size. [email protected]:

The INT, smallint, tinyint, and other fields set in MYSQL are all converted into strings, but the primary key is not converted into strings. How can I set it? The INT, smallint, tinyint, and other fields set in MYSQL are all converted into strings,