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MySQLi Articles
Page 233 of 341
MySQL query to set my auto increment column ( id ) to zero or reset the value of auto increment field?
Use ALTER table to set the auto_increment column to 0 or reset with another valueALTER TABLE yourTableName AUTO_INCREMENT=0;The above syntax will begin from 1.Let us first create a table −mysql> create table DemoTable698 ( ClientId int NOT NULL AUTO_INCREMENT PRIMARY KEY ) auto_increment=109; Query OK, 0 rows affected (0.88 sec)Here is the query to reset the auto_increment value to 0 −mysql> alter table DemoTable698 AUTO_INCREMENT=0; Query OK, 0 rows affected (0.21 sec) Records: 0 Duplicates: 0 Warnings: 0Insert some records in the table using insert command. Here, we haven’t inserted anything since we want to display auto increment value ...
Read MoreHow to return table from MySQL function?
You cannot return table from MySQL function. The function can return string, integer, char etc. To return table from MySQL, use stored procedure, not function.Let us first create a table −mysql> create table DemoTable696 ( Id int, Name varchar(100) ); Query OK, 0 rows affected (0.77 sec)Insert some records in the table using insert command −mysql> insert into DemoTable696 values(100, 'Mike'); Query OK, 1 row affected (0.14 sec) mysql> insert into DemoTable696 values(101, 'Sam'); Query OK, 1 row affected (0.17 sec) mysql> insert into DemoTable696 values(102, 'Adam'); Query OK, 1 row affected (0.14 sec) mysql> insert into DemoTable696 ...
Read MoreHow to implement Count (*) as variable from MySQL to display the number of records in a table?
The alias name can be used as a variable name in MySQL as shown in the below syntax −select count(*) AS anyAliasName from yourTableName;Let us first create a table −mysql> create table DemoTable695 ( FirstName varchar(100) ); Query OK, 0 rows affected (0.72 sec)Insert some records in the table using insert command −mysql> insert into DemoTable695 values('Chris'); Query OK, 1 row affected (0.17 sec) mysql> insert into DemoTable695 values('Robert'); Query OK, 1 row affected (0.15 sec) mysql> insert into DemoTable695 values('David'); Query OK, 1 row affected (0.15 sec) mysql> insert into DemoTable695 values('Mike'); Query OK, 1 row affected (0.16 ...
Read MoreHow to get the first and last record of the table in MySQL?
To get the first and last record, use UNION. LIMIT is also used to get the number of records you want.Let us first create a table −mysql> create table DemoTable694 ( EmployeeId int NOT NULL AUTO_INCREMENT PRIMARY KEY, EmployeeName varchar(100), EmployeeSalary int ); Query OK, 0 rows affected (0.58 sec)Insert some records in the table using insert command −mysql> insert into DemoTable694(EmployeeName, EmployeeSalary) values('Chris', 457647); Query OK, 1 row affected (0.15 sec) mysql> insert into DemoTable694(EmployeeName, EmployeeSalary) values('Robert', 90883); Query OK, 1 row affected (0.25 sec) mysql> insert into DemoTable694(EmployeeName, EmployeeSalary) values('David', 123532); Query OK, 1 row ...
Read MoreCan we use "When" as column name in CREATE TABLE statement?
Before beginning, let us try to set ‘when’ as column name while using CREATE TABLE statement −mysql> create table DemoTable693( StudentId int NOT NULL AUTO_INCREMENT PRIMARY KEY, StudentName varchar(100), When datetime );This will produce the following output. An error would be visible:ERROR 1064 (42000): You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'When datetime at line 5You need to wrap the reserved word using backticks, for example, `when`. Let us first create a table and implement the same:mysql> create table ...
Read MoreGet a list of MySQL databases and version?
To get a list of MySQL databases, following is the syntax -show databases;To get the server version, you can use the below syntax -select version();Let us implement the above syntax to get a list of MySQL databases and version -mysql> show databases;This will produce the following output displaying all the databases -+---------------------------+ | Database | +---------------------------+ | bothinnodbandmyisam | | business | | commandline | | customer-tracker | | customer_tracker_database ...
Read MoreHow to group by date regardless of time in MySQL?
When you have identical dates in a table with different time values for each, you can group them easily with GROUP BY DATE.Let us first create a table -mysql> create table DemoTable692 (DueDatetime datetime); Query OK, 0 rows affected (0.97 sec)Insert some records in the table using insert command:mysql> insert into DemoTable692 values('2019-07-21 10:20:00'); Query OK, 1 row affected (0.18 sec) mysql> insert into DemoTable692 values('2019-06-11 11:00:10'); Query OK, 1 row affected (0.24 sec) mysql> insert into DemoTable692 values('2019-07-21 11:00:10'); Query OK, 1 row affected (1.97 sec) mysql> insert into DemoTable692 values('2019-07-21 12:10:10'); Query OK, 1 row affected (0.18 sec)Display ...
Read MoreAdd a column to a MySQL table which is the result of concatenation of text and value from another auto increment column?
For this, you can use LAST_INSERT_ID(). Let us first create a table −mysql> create table DemoTable ( UserId int(6) unsigned zerofill NOT NULL AUTO_INCREMENT, UserAutoIncrement char(100) default null, PRIMARY KEY(UserId) ); Query OK, 0 rows affected (0.72 sec)Insert some records in the table using insert command −mysql> insert into DemoTable values(); Query OK, 1 row affected (0.13 sec)Display all records from the table using select statement −mysql> select *from DemoTable;Output+--------+-------------------+ | UserId | UserAutoIncrement | +--------+-------------------+ | 000001 | NULL | +--------+-------------------+ ...
Read MoreSet a filter on field type to fetch MySQL columns with type text?
To set a filter for type, you can use below syntax −SELECT TABLE_NAME, COLUMN_NAME FROM INFORMATION_SCHEMA.COLUMNS WHERE DATA_TYPE = 'yourDataTypeName';Let us implement the above syntax to show fields only with field type text −mysql> SELECT TABLE_NAME, COLUMN_NAME FROM INFORMATION_SCHEMA.COLUMNS WHERE DATA_TYPE = 'text';This will produce the following output −+---------------------------------------------+--------------------------------+ | TABLE_NAME | COLUMN_NAME | +---------------------------------------------+--------------------------------+ | COLUMNS ...
Read MoreDisplay all deadlock logs in MySQL?
First of all, you need to enable innodb_print_all_deadlocks. Following is the syntax −set global innodb_print_all_deadlocks=1;After executing the above statement, let us execute the below syntax in order to display all deadlock logs −show engine innodb status;Let us implement the above syntax −mysql> set global innodb_print_all_deadlocks=1; Query OK, 0 rows affected (0.00 sec) mysql> show engine innodb status;This will produce the following output −+--------+------+---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+ | Type | Name | Status ...
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