MySQLi Articles - Page 132 of 422

Let’s see when the #1054 error occurs in MySQL. While inserting a varchar value, if you will forget to add single quotes, then this error will arise. Following is the error −mysql> insert into DemoTable798 values(100, Adam); ERROR 1054 (42S22): Unknown column 'Adam' in 'field list'You need to use single quotes around the string value to fix this error as shown below −mysql> insert into DemoTable798 values(100, ’Adam’);Let us first create a table −mysql> create table DemoTable798 ( StudentId int, StudentName varchar(100) ); Query OK, 0 rows affected (0.51 sec)Insert some records in the ... Read More

The correct datetime format for MySQL database is as follows −‘YYYY-MM-DD HH:M:SS’Let us first create a table −mysql> create table DemoTable797 ( ArrivalDatetime datetime ); Query OK, 0 rows affected (0.68 sec)Insert some records in the table using insert command −mysql> insert into DemoTable797 values(NOW()); Query OK, 1 row affected (0.15 sec) mysql> insert into DemoTable797 values('2016-12-21 12:50:34'); Query OK, 1 row affected (0.17 sec) mysql> insert into DemoTable797 values('2017-03-01 17:40:21'); Query OK, 1 row affected (0.24 sec)Display all records from the table using select statement −mysql> select *from DemoTable797;This will produce the following output. We have ... Read More

Use the DAYNAME() to display the day name from records with Date of Birth.Let us first create a table −mysql> create table DemoTable795 ( DateOfBirth date ); Query OK, 0 rows affected (0.61 sec)Insert some records in the table using insert command −mysql> insert into DemoTable795 values('1996-01-21'); Query OK, 1 row affected (0.14 sec) mysql> insert into DemoTable795 values('2004-11-01'); Query OK, 1 row affected (0.12 sec) mysql> insert into DemoTable795 values('1990-03-31'); Query OK, 1 row affected (0.12 sec) mysql> insert into DemoTable795 values('2010-12-03'); Query OK, 1 row affected (0.13 sec)Display all records from the table using select ... Read More

To display number of fields in MySQL, use the COUNT(*). Following is the syntax −select COUNT(*) AS anyAliasName from INFORMATION_SCHEMA.COLUMNS where table_name = yourTableName AND TABLE_SCHEMA = yourDatabaseName;Let us first create a table −mysql> create table DemoTable794 ( ClientId int NOT NULL AUTO_INCREMENT PRIMARY KEY, ClientName varchar(100), ClientAge int, ClientCountryName varchar(100) ); Query OK, 0 rows affected (1.61 sec)Following is the query to get the number of fields in MySQL −mysql> select COUNT(*) AS TOTAL_NUMBER_OF_COLUMNS from INFORMATION_SCHEMA.COLUMNS where table_name = 'DemoTable794' AND ... Read More

To check records which are NULL, use IS NULL. However, to exclude any of the records, use the NOT IN clause. Use both of them in the same query.Let us first create a table −mysql> create table DemoTable793 ( StudentId int NOT NULL AUTO_INCREMENT PRIMARY KEY, StudentName varchar(100) ); Query OK, 0 rows affected (0.81 sec)Insert some records in the table using insert command −mysql> insert into DemoTable793(StudentName) values('Adam'); Query OK, 1 row affected (0.14 sec) mysql> insert into DemoTable793(StudentName) values('Bob'); Query OK, 1 row affected (0.16 sec) mysql> insert into DemoTable793(StudentName) values(null); Query ... Read More

To reshuffle the values in a table, use MySQL RAND().Let us first create a table −mysql> create table DemoTable792 ( Name varchar(100), Subject varchar(100) ); Query OK, 0 rows affected (0.66 sec)Insert some records in the table using insert command −mysql> insert into DemoTable792 values('Chris', 'MySQL'); Query OK, 1 row affected (0.17 sec) mysql> insert into DemoTable792 values('David', 'MySQL'); Query OK, 1 row affected (0.22 sec) mysql> insert into DemoTable792 values('Robert', 'MongoDB'); Query OK, 1 row affected (0.20 sec) mysql> insert into DemoTable792 values('Carol', 'MongoDB'); Query OK, 1 row affected (0.18 sec)Display all records ... Read More

Use NOT IN() to exclude some of the values from the table.Let us first create a table −mysql> create table DemoTable791 ( Id int NOT NULL AUTO_INCREMENT PRIMARY KEY, FirstName varchar(100) ); Query OK, 0 rows affected (0.61 sec)Insert some records in the table using insert command −mysql> insert into DemoTable791(FirstName) values('Chris'); Query OK, 1 row affected (0.16 sec) mysql> insert into DemoTable791(FirstName) values('Robert'); Query OK, 1 row affected (0.14 sec) mysql> insert into DemoTable791(FirstName) values('David'); Query OK, 1 row affected (0.14 sec) mysql> insert into DemoTable791(FirstName) values('Mike'); Query OK, 1 row affected (0.11 ... Read More

Let us first create a table −mysql> create table DemoTable790 ( Score1 int, Score2 int ); Query OK, 0 rows affected (0.45 sec)Insert some records in the table using insert command −mysql> insert into DemoTable790 values(98, 76); Query OK, 1 row affected (0.12 sec) mysql> insert into DemoTable790 values(78, 89); Query OK, 1 row affected (0.12 sec) mysql> insert into DemoTable790 values(85, 68); Query OK, 1 row affected (0.14 sec)Display all records from the table using select statement −mysql> select *from DemoTable790;This will produce the following output -+--------+--------+ | Score1 | Score2 | +--------+--------+ ... Read More

To check for the 1st letter of the first and last name, you need to use the LEFT().Let us first create a table −mysql> create table DemoTable789 ( FirstName varchar(100), LastName varchar(100) ); Query OK, 0 rows affected (0.78 sec)Insert some records in the table using insert command −mysql> insert into DemoTable789 values('Adam', 'Smith'); Query OK, 1 row affected (0.12 sec) mysql> insert into DemoTable789 values('Tom', 'Taylor'); Query OK, 1 row affected (0.23 sec) mysql> insert into DemoTable789 values('Bob', 'Brown'); Query OK, 1 row affected (0.12 sec) mysql> insert into DemoTable789 values('David', 'Miller'); Query ... Read More

Use ORDER BY to sort data for duplicate record.Let us first create a table −mysql> create table DemoTable788 ( FirstName varchar(100), Score int ); Query OK, 0 rows affected (1.89 sec)Insert some records in the table using insert command −mysql> insert into DemoTable788 values('Chris', 78); Query OK, 1 row affected (0.20 sec) mysql> insert into DemoTable788 values('Robert', 67); Query OK, 1 row affected (0.19 sec) mysql> insert into DemoTable788 values('Chris', 98); Query OK, 1 row affected (0.12 sec) mysql> insert into DemoTable788 values('Chris', 56); Query OK, 1 row affected (0.15 sec) mysql> insert into ... Read More