- Data Structure
- Networking
- RDBMS
- Operating System
- Java
- MS Excel
- iOS
- HTML
- CSS
- Android
- Python
- C Programming
- C++
- C#
- MongoDB
- MySQL
- Javascript
- PHP
- Physics
- Chemistry
- Biology
- Mathematics
- English
- Economics
- Psychology
- Social Studies
- Fashion Studies
- Legal Studies
- Selected Reading
- UPSC IAS Exams Notes
- Developer's Best Practices
- Questions and Answers
- Effective Resume Writing
- HR Interview Questions
- Computer Glossary
- Who is Who
Found 4219 Articles for MySQLi
421 Views
To get a list of non-empty tables in a particular MySQL database, the following is the syntax −SELECT table_type, table_name, table_schema from information_schema.tables where table_rows >= 1 and table_schema = 'yourDatabaseName';Implement the above syntax for your database. Here, our database is “test”. The query is as follows −mysql> select table_type, table_name ,table_schema from information_schema.tables −> where table_rows >= 1 and table_schema = 'test';The following is the output displaying the non-empty tables in the database “test” −+------------+------------------------------+--------------+ | TABLE_TYPE | TABLE_NAME | TABLE_SCHEMA | +------------+------------------------------+--------------+ | BASE TABLE | add30minutesdemo ... Read More
4K+ Views
To find the number of days in month, use the below syntax.select DAY(LAST_DAY(yourColumnName)) 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 DaysInaGivenMonth -> ( -> MonthName datetime -> ); Query OK, 0 rows affected (1.62 sec)Insert some records in the table using insert command. The query is as follows.mysql> insert into DaysInaGivenMonth values(now()); Query OK, 1 row affected (0.24 sec) mysql> insert into DaysInaGivenMonth values(date_add(now(), interval -1 month)); Query OK, 1 row affected (0.16 sec) mysql> insert into DaysInaGivenMonth values(date_add(now(), interval ... Read More
669 Views
You can create DATETIME from DATE and TIME with the help of ADDTIME() function in MySQL. The syntax is as follows −SELECT ADDTIME(CONVERT(yourDateColumnName, datetime), yourTimeColumnName) as anyVariableName from yourTableName;To understand the above concept, let us create a table. The query to create a table is as follows −mysql> create table DateTime −> ( −> DueDate date, −> DueTime time −> ); Query OK, 0 rows affected (1.19 sec)Now you can insert date and time separately. The query to insert is as follows −mysql> insert into DateTime values(curdate(), now()); ... Read More
602 Views
The Sum() is an aggregate function in MySQL. You can use sum query with if condition. To understand the sum query with if condition, let us create a table.The query to create a table −mysql> create table SumWithIfCondition −> ( −> ModeOfPayment varchar(100) −> , −> Amount int −> ); Query OK, 0 rows affected (1.60 sec)Insert some records in the table using insert command. The query is as follows −mysql> insert into SumWithIfCondition values('Offline', 10); Query OK, 1 row affected (0.21 sec) mysql> insert into SumWithIfCondition values('Online', 100); Query OK, 1 row affected ... Read More
418 Views
To not allow any duplicate entry to be entered in a MySQL table, you need to add unique key. The syntax is as follows −alter ignore table yourTableName add constraint unique key(yourColumName);The above syntax sets unique key. To understand the above syntax, let us create a table.The following is the query to create a table −mysql> create table RemoveDuplicateEntry −> ( −> Id int, −> Name varchar(100) −> )ENGINE = MyISAM; Query OK, 0 rows affected (0.15 sec)Now you can implement the syntax discussed in the beginning. The query is as follows −mysql> alter table ... Read More
2K+ Views
You can check multiple columns for one value with the help of IN operator. The syntax is as follows −select *from yourTableName where value IN(yourColumnName1, yourColumnName2, ......N);To understand the above concept, let us create a table with some columns. The query to create a table is as follows −mysql> create table OneValueFromAllColumns −> ( −> StudentId int, −> StudentFirstname varchar(200), −> StudentLastname varchar(200), −> StudentAge int −> ); Query OK, 0 rows affected (1.41 sec)Insert some records in the table with the ... Read More
1K+ Views
To achieve this, the following is the syntax.UPDATE yourTableName set yourColumnName=concat(ifnull(yourColumnName, ””), ’anyValue1, anyValue2, anyValue);To understand the above syntax, let us first create a table. The query to create a table is as follows -mysql> create table AppendDataDemo -> ( -> StudentId int, -> StudentName varchar(100), -> StudentAge int -> ); Query OK, 0 rows affected (1.54 sec)Insert some records in the table using insert command. The query is as follows.mysql> insert into AppendDataDemo values(101, 'John', 23); Query OK, 1 row affected (0.24 sec) mysql> insert into AppendDataDemo values(102, null, 24); Query OK, 1 row affected (0.74 sec) ... Read More
16K+ Views
You can use LIKE with OR operator which works same as IN operator.Let us see the syntax for both the cases −Case 1 − Using Like with OR operator.select *from yourTableName where yourColumnName Like ‘Value1’ or yourColumnName Like ‘Value2’ or yourColumnName Like ‘Value3’ . . . NCase 2 − Using IN operator.select *from yourTableName where IN(value1, value2, value3, .....N);To understand both the syntaxes, let us create a table. The query to create a table is as follows −mysql> create table LikeDemo −> ( −> Id varchar(20) −> ); Query OK, 0 rows affected (0.58 sec)Now you can insert records in ... Read More
1K+ Views
You can do this with the help of information_schema.tables. The syntax is as follows -SELECT TABLE_NAME, table_rows, data_length, index_length, round(((data_length + index_length) / 1024 / 1024), 2) "MB Size" FROM information_schema.TABLES WHERE table_schema = "yourDatabaseName" ORDER BY (data_length + index_length) ASC;To understand the above syntax, let us implement it for any database. Here, I am using database TEST. Let us see the query for our database TEST.mysql> SELECT TABLE_NAME, table_rows, data_length, index_length, -> round(((data_length + index_length) / 1024 / 1024), 2) "MB Size" -> FROM information_schema.TABLES WHERE table_schema = "test" -> ORDER BY (data_length + index_length) ASC;The following is the ... Read More
4K+ Views
To avoid this type of error in MySQL stored procedure, you need to change the delimiter ; to //.Suppose if you are using stored procedure or triggers or even function then you need to change the delimiter. The syntax is as follows.DELIMITER // CREATE PROCEDURE yourProcedureName() BEGIN Statement1, . . N END; // DELIMITER ;To understand the above syntax, let us create a stored procedure. The query to create a stored procedure is ... Read More