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MySQLi Articles
Page 309 of 341
Delimiters in MySQL?
Delimiters can be used when you need to define the stored procedures, function as well as to create triggers. The default delimiter is semicolon.You can change the delimiters to create procedures and so on. However, but if you are considering multiple statements, then you need to use different delimiters like $$ or //.Here we have a table “GetRecordFromNow” wherein the following are the records −+---------------------+ | YourDateTime | +---------------------+ | 2018-12-07 22:30:18 | | 2018-12-03 22:30:31 | | 2018-12-02 22:30:41 | | 2018-12-01 22:30:56 | | 2018-12-03 22:31:04 | +---------------------+ 5 rows in ...
Read MoreHow to get primary key of a table in MySQL?
To get the primary key of a table, you can use the show command. The syntax is as follows −SHOW INDEX FROM yourDatebaseName.yourTableName WHERE Key_name = 'PRIMARY';Suppose, we have a table with two primary keys; one of them is “Id” and second is “RollNum". The query for a table is as follows −mysql> create table TwoOrMorePrimary −> ( −> Id int, −> Name varchar(200), −> RollNum int −> , −> Primary key(Id, Age) −> ); Query OK, 0 rows affected (0.85 sec)Apply the above syntax to get primary key of a table. ...
Read MoreMySQL command line client for Windows?
In order to install MySQL command line client for Windows, you need to visit the following URL to get the download link https://dev.mysql.com/downloads/mysql/ −The snapshot is as follows −After that you need to select operating system. The snapshot is as follows −You need to choose Windows (x86, 32/64-bit) and download the installer.
Read MoreDo a select in MySQL based only on month and year?
To select MySQL based on month and year, use in-built function YEAR() and MONTH(). The syntax is as follows −select *from yourTableName where YEAR(yourColumnName) = YearValue AND MONTH(yourColumnName) = monthValue;To understand the above syntax, let us create a table. The query to create a table is as follows −mysql> create table selectDataOnYearandMonthDemo −> ( −> BookId int, −> BookName varchar(100), −> BookDueDate datetime −> ); Query OK, 0 rows affected (0.57 sec)Now you can insert some records in the table. The query is as ...
Read MoreCheck if a user exists in MySQL and drop it?
To check how many users are present in MySQL, use MySQL.user table. The syntax is as follows to check how many users are present.mysql> SELECT User FROM mysql.user;The following output displays the users −+------------------+ | User | +------------------+ | Mac | | Manish | | mysql.infoschema | | mysql.session | | mysql.sys | | root ...
Read MoreHow to front pad zip code with "0" in MySQL?
To front pad zip code with 0, use LPAD() function in MySQL. The syntax is as follows −SELECT LPAD(yourColumnName, columnWidth+1, '0') as anyVariableName from yourTableName;To understand the above concept of LPAD() to add front pad zip code with 0, let us create a table. One of the columns of the table is Zip Code. The following is the query to create a table.mysql> create table ZipCodePadWithZeroDemo −> ( −> Name varchar(200), −> YourZipCode int(6) −> ); Query OK, 0 rows affected (0.44 sec)Insert some records in the table. The query to insert records is as follows ...
Read MoreGet the difference between two timestamps in seconds in MySQL?
To get difference between two timestamps in seconds, use two in-built functions TIME_TO_SEC() and TIMEDIFF() in MySQL. The syntax is as follows −select time_to_sec(timediff(yourCoulnName1, yourCoulnName2)) as anyVariableName from yourTableName;To understand the above concept, let us first create a table. The query to create a table.mysql> create table TimeToSecond −> ( −> MyTime timestamp, −> YourTime timestamp −> ); Query OK, 0 rows affected (0.48 sec)Now you can insert some datetime values in the table. The query is as follows −mysql> insert into TimeToSecond values('2016-05-10 10:02:00', '2016-05-10 10:00:00'); Query ...
Read MoreCompare DATE string with string from MySQL DATETIME field?
You can compare DATE string with string from DATETIME field with the help of DATE() function in MySQL.The syntax is as follows −select *from yourTableName where DATE(yourColumnName) = ’anyDateString’;To understand the above syntax, let us create a table and set some datetime values in the table. The query to create a table −mysql> create table DateTimeDemo −> ( −> ArrivalTime datetime −> ); Query OK, 0 rows affected (0.61 sec)Let us insert some records in the table with the help of insert command. The following is the query to insert records ...
Read MoreHow to store Query Result in a variable using MySQL?
To store query result in a variable with MySQL, use the SET command. The syntax is as follows −SET @anyVariableName = ( yourQuery);To understand the above concept, let us create a table. The following is the query to create a table −mysql> create table QueryResultDemo −> ( −> Price int −> ); Query OK, 0 rows affected (0.59 sec)Now let us insert some records into the table. The following is the query to insert records −mysql> insert into QueryResultDemo values(100); Query OK, 1 row affected (0.17 sec) mysql> insert into QueryResultDemo values(20); Query OK, 1 row ...
Read MoreHow can I describe all tables in the database through a single statement in MySQL?
You can use INFORMATION_SCHEMA.COLUMNS to describe all tables in database through a single statement. The syntax is as follows.SELECT *FROM INFORMATION_SCHEMA.COLUMNS WHERE TABLE_SCHEMA=’yourDatabaseName’\GHere I am using my database sample with two tables.The table names are as follows −mytableyourtableImplement the above syntax for your database. The query is as follows −mysql> select * FROM information_schema.columns WHERE table_schema = 'sample'\GThe following is the output describing the two tables in our database.*************************** 1. row *************************** TABLE_CATALOG: def TABLE_SCHEMA: sample TABLE_NAME: mytable COLUMN_NAME: id ORDINAL_POSITION: 1 COLUMN_DEFAULT: NULL IS_NULLABLE: YES DATA_TYPE: int CHARACTER_MAXIMUM_LENGTH: NULL CHARACTER_OCTET_LENGTH: NULL NUMERIC_PRECISION: 10 NUMERIC_SCALE: 0 DATETIME_PRECISION: NULL CHARACTER_SET_NAME: NULL ...
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