Found 4219 Articles for MySQLi

To query for string fields with a specific length, use the char_length() or length() from MySQL.SyntaxThe syntax is as follows −Case 1 − Use of char_length()This can be used when we are taking length in a number of characters.The syntax −select *from yourTableName where char_length(yourColumnName)=anySpecificLengthValue;Case 2 − Use of length()This can be used when we are taking the length in bytes.The syntax −select *from yourTableName where length(yourColumnName)=anySpecificLengthValue;To understand the above concept, let us first create a table. The query to create a table is as follows −mysql> create table StringWithSpecificLength -> ( -> Id int, -> Name varchar(100), -> FavouriteLanguage ... Read More

Let us learn some points about TINYINT type in MySQL −The TINYINT type takes 1 byte i.e. 8 bits.The TINYINT(N), where N indicates the display width you want.For example, TINYINT(1) can be used to display width which is 1.Let us learn about the minimum and maximum values −The maximum value for tinyint is= (2(8-1)-1) = 127 The minimum value for tinyint is = -(2(8-1)) = -128.The value will be between -128 to 127. This means TINYINT (1) does not affect the maximum and minimum value of tinyint.Let us check it −Firstly, create a table with a column set as TINYINT ... Read More

You can use date-sub() and now() function from MySQL to fetch the rows added in last hour.SyntaxThe syntax is as follows −select *from yourTableName where yourDateTimeColumnName create table LastHourRecords -> ( -> Id int, -> Name varchar(100), -> Login datetime -> ); Query OK, 0 rows affected (0.67 sec)Insert records in the form of datetime using insert command. The query to insert record is as follows −mysql> insert into LastHourRecords values(1, 'John', ' 2018-12-19 10:00:00'); Query OK, 1 row affected (0.17 sec) mysql> insert into LastHourRecords values(2, 'Carol', '2018-12-19 10:10:00'); Query OK, 1 row affected (0.15 sec) ... Read More

To get the original value, use the following syntax −Syntaxselect yourBitColumnName+0 from yourTableName;The above syntax cast the bit column to an integer. To understand the above concept, let us create a table and check how the returning value is blank. We will also see how to get the original value.The query to create a table.mysql> create table BitDemo -> ( -> hasValidId bit not null -> ); Query OK, 0 rows affected (1.21 sec)Insert some records in the table using insert command. The query to insert records is as follows −mysql> insert into BitDemo values(1); Query OK, 1 row affected ... Read More

Instead of simulating an array variable, use temporary table in MySQL. The syntax is as follows −create temporary table if not exists yourTemporaryTableName select yourColumnName1, yourColumnName2, ......N from yourTableName where conditionTo understand the above syntax, let us first create a table. The query to create a table is as follows −mysql> create table SimulateArrayDemo -> ( -> Id int, -> FirstName varchar(100), -> LastName varchar(100 -> ) -> ); Query OK, 0 rows affected (1.25 sec)Insert some records in the table using ... Read More

Whenever you want all the values like not null for a column then use count(*). This is faster than using count() method.The syntax to use count(*) is as follows −select count(*) as anyVariableName from yourTableName;To understand the above concept, let us first create a table. The query to create a table is as follows −mysql> create table CountingDemo    -> (    -> BookId int    -> ); Query OK, 0 rows affected (0.60 sec)Insert some records in the table using insert command. The query is as follows −mysql> insert into CountingDemo values(100); Query OK, 1 row affected (0.13 sec) ... Read More

To simulate a print statement in MySQL, you can use select statement. The syntax is as follows −SELECT ‘anyStringValue’ as ’ ‘;You can check the above syntax at the MySQL command line client.Case 1To print a string.mysql> select 'HELLO MYSQL' as ' ';Output+-------------+ |             | +-------------+ | HELLO MYSQL | +-------------+ 1 row in set (0.00 sec)Case 2a) To print integer, use the following query −mysql> select 23 as ' ';Output+----+ |    | +----+ | 23 | +----+ 1 row in set (0.00 sec)b) To print float or double type, use the following ... Read More

In order to get the date from the timestamp, you can use DATE() function from MySQL.The syntax is as follows −SyntaxSELECT DATE(yourTimestampColumnName) as anyVariableName from yourTableName;To understand the above syntax, let us first create a table. The query to create a table is as follows −mysql> create table DateFromTimestamp -> ( -> ShippingDateTime timestamp -> ); Query OK, 0 rows affected (0.60 sec)Insert date and time for the column ShippingDateTime we created above.The query to insert record is as follows −mysql> insert into DateFromTimestamp values('2012-12-26 13:24:35'); Query OK, 1 row affected (0.14 sec) mysql> insert into DateFromTimestamp values('2013-11-26 14:36:40'); ... Read More

To make a primary key start from 1000, you need to alter your table and set to auto_increment with value 1000. The syntax is as follows −alter table yourTableName auto_increment=1000;To understand the above syntax, let us first create a table. The query to create a table is as follows −mysql> create table PrimaryKey1000Demo    -> (    -> ProductId int auto_increment,    -> PRIMARY KEY(ProductId)    -> ); Query OK, 0 rows affected (0.56 sec)Now here is the query that will update the primary key to start from 1000 −mysql> alter table PrimaryKey1000Demo auto_increment=1000; Query OK, 0 rows affected (0.20 ... Read More

You need to store the date as the complete date time rather than storing only month and year. If you declare as a datetime then you can extract the month and year using MONTH() and YEAR() function from MySQL.The syntax is as follows −select MONTH(yourDateTimeColumnName) as anyVariableName1, YEAR(yourDateTimeColumnName) as anyVariableName2 from yourTableName;To understand the above syntax, let us create a table. The query to create a table is as follows −mysql> create table OnlyMonthandYear    -> (       -> DueDateTime datetime    -> ); Query OK, 0 rows affected (0.56 sec)Insert date in the table using insert command. ... Read More