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MySQLi Articles
Page 43 of 341
int(5) vs. int(10) in MySQL?
The value in the parentheses is used to display only the width and sets the zerofill. The width is 5 for int(5), whereas 10 for int(10). Let us see another example with a different width value set for int.Let us first create a table. Here, we have set the int to int(11) and int(13). The following is the query to create a table −mysql> create table intVsIntAnyThingDemo −> ( −> Number1 int(11) unsigned zerofill, −> Number int(13) unsigned zerofill −> ); Query OK, 0 rows affected (1.17 sec)Now you can insert record in the table with the help of insert ...
Read MoreMySQL Select Multiple VALUES?
To select multiple values, you can use where clause with OR and IN operator.The syntax is as follows −Case 1 − Using ORselect *from yourTablename where yourColumnName = value1 or yourColumnName = value2 or yourColumnName = value3, .........N;Case 2 − Using INselect *from yourTableName where yourColumnName IN(value1, value2, ....N);To understand the above syntax, let us create a table. The following is the query to create a table −mysql> create table selectMultipleValues −> ( −> BookId int, −> BookName varchar(200) −> ); Query OK, 0 rows affected (1.68 sec)Now you can insert some records in the table with the help of ...
Read MoreHow to use user variables in MySQL LIKE clause?
Using the CONCAT() function, we can work with user variables in LIKE clause. The syntax is as follows.set @anyVariableName='anyValue'; select yourColumnName1, yourColumnName2, yourColumnName3, ...N from yourTableName whereyourColumnName like CONCAT('%', @anyVariableName, '%');To understand the above syntax, let us first create a table. The query to create a table is as follows.mysql> create table UserVariableInLike -> ( -> id int, -> Name varchar(100), -> Age int -> ); Query OK, 0 rows affected (0.83 sec)Insert records in the table using insert command. The query is as follows.mysql> insert into UserVariableInLike values(101, 'John', 23); Query OK, 1 row affected (0.23 sec) mysql> ...
Read MoreConcat a string to SELECT * in MySQL?
To concat a string, use the CONCAT() function from MySQL as shown in the below syntaxSELECT CONCAT(yourColumnName1, ’anyConcatenationString’), CONCAT(yourColumnName2, ’anyC oncatenationString’), ....N from yourTableName;To understand the above syntax, let us first create a table. The query to create a table is as followsmysql> create table selectConcat -> ( -> StudentId int, -> StudentName varchar(100), -> StudentAge int -> ); Query OK, 0 rows affected (1.32 sec)Insert some records in the table using insert command. The query is as followsmysql> insert into selectConcat values(1, 'Carol', 23); Query OK, 1 row affected (0.19 sec) mysql> insert into selectConcat values(2, 'John', 24); ...
Read MoreHow to set max_connections in MySQL Programmatically?
To set max_connections in MySQL programmatically, you can use SET command. The syntax is as follows −SET GLOBAL max_connections=yourIntegerValue;Let us implement the above query to set maximum connections. The query is as follows −mysql> set global max_connections=1000; Query OK, 0 rows affected (0.04 sec)Check maximum connections are set or not, using the show variables command. The query is as follows.mysql> show variables like 'max_connections';The following is the output.+-----------------+-------+ | Variable_name | Value | +-----------------+-------+ | max_connections | 1000 | +-----------------+-------+ 1 row in set (0.18 sec)
Read MoreHow do you force MySQL LIKE to be case sensitive?
To force MySQL LIKE to be case sensitive with the help of LIKE BINARY, the following is the syntax −select yourColumnName like binary 'anyStringValue' from yourTableName;To understand the above concept, let us create a table. The following is the query to create a table −mysql> create table LikeBinaryDemo −> ( −> Name varchar(200) −> ); Query OK, 0 rows affected (0.58 sec)Now you can insert records with small letters to force the MySQL LIKE to be case sensitive −mysql> insert into LikeBinaryDemo values('john'); Query OK, 1 row affected (0.12 sec)Display the records in the table. The query ...
Read MoreMySQL datatype to store month and year only?
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 MoreHow can I simulate a print statement in MySQL?
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 MoreAvoid placing password on command line with MySQL Utilities?
First you need to reach the location of “my.cnf” with the help of below query for MySQL Utilities. The query is as follows −mysql> select @@datadir;The following is the output that display where “my.conf” is −+---------------------------------------------+ | @@datadir | +---------------------------------------------+ | C:\ProgramData\MySQL\MySQL Server 8.0\Data\ | +---------------------------------------------+ 1 row in set (0.00 sec)Follow the above path in order to open the “my.cnf” file. The snapshot of “my.cnf” location is as follows −Now you can put the below MySQL Utilities in my.cnf which is as ...
Read MoreHow to resolve the ERROR 1115 (42000): Unknown character set: 'utf8mb4'?
You will get this type of error when your MySQL version is below 5.5.3. This is because “utf8mb4” introduced in MySQL version 5.5.3.Firstly, you need to check the current version. If its less than 5.5.3, then you need to upgrade to solve the above error.Check the current version −mysql> select version();Here, our MySQL version is over 5.5.3 −+-----------+ | version() | +-----------+ | 8.0.12 | +-----------+ 1 row in set (0.00 sec)Now the same query that gave an error 1115, will display correct result. To check all character set in MySQL now, use the below query.mysql> show character set;The ...
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