For this, use IF() with IS NULL property. Let us first create a table −mysql> create table DemoTable1976    (    FirstName varchar(20),    LastName varchar(20)    ); Query OK, 0 rows affected (0.00 sec)Insert some records in the table using insert command −mysql> insert into DemoTable1976 values('John', 'Doe'); Query OK, 1 row affected (0.00 sec) mysql> insert into DemoTable1976 values('John', NULL); Query OK, 1 row affected (0.00 sec) mysql> insert into DemoTable1976 values(NULL, 'Miller'); Query OK, 1 row affected (0.00 sec) mysql> insert into DemoTable1976 values('Chris', 'Brown'); Query OK, 1 row affected (0.00 sec)Display all records from the table ... Read More

Let us first create a table −mysql> create table DemoTable1975    (    StudentName varchar(20),    StudentMarks int    ); Query OK, 0 rows affected (0.00 sec)Insert some records in the table using insert command −mysql> insert into DemoTable1975 values('John', 45); Query OK, 1 row affected (0.00 sec) mysql> insert into DemoTable1975 values('Chris', 67); Query OK, 1 row affected (0.00 sec) mysql> insert into DemoTable1975 values('David', 59); Query OK, 1 row affected (0.00 sec) mysql> insert into DemoTable1975 values('Bob', NULL); Query OK, 1 row affected (0.00 sec)Display all records from the table using select statement −mysql> select * from DemoTable1975;This ... Read More

For this, use prepared statement. Let us first create a table −mysql> create table DemoTable1973    (    StudentId int,    StudentName varchar(20)    ); Query OK, 0 rows affected (0.00 sec)Insert some records in the table using insert command −mysql> insert into DemoTable1973 values(101, 'Chris'); Query OK, 1 row affected (0.00 sec) mysql> insert into DemoTable1973 values(102, 'John Doe'); Query OK, 1 row affected (0.00 sec) mysql> insert into DemoTable1973 values(103, 'David'); Query OK, 1 row affected (0.00 sec) mysql> insert into DemoTable1973 values(104, 'John Smith'); Query OK, 1 row affected (0.00 sec)Display all records from the table using ... Read More

Let us first create a table −mysql> create table DemoTable1972    (    Section char(1),    StudentName varchar(20)    ); Query OK, 0 rows affected (0.00 sec)Insert some records in the table using insert command −mysql> insert into DemoTable1972 values('D', 'Chris'); Query OK, 1 row affected (0.00 sec) mysql> insert into DemoTable1972 values('B', 'David'); Query OK, 1 row affected (0.00 sec) mysql> insert into DemoTable1972 values('A', 'Mike'); Query OK, 1 row affected (0.00 sec) mysql> insert into DemoTable1972 values('C', 'Carol'); Query OK, 1 row affected (0.00 sec)Display all records from the table using select statement −mysql> select * from DemoTable1972;This ... Read More

Let us first create a table −mysql> create table DemoTable1971    (    StudentId int NOT NULL AUTO_INCREMENT PRIMARY KEY,    StudentName varchar(20),    StudentPassword int    ); Query OK, 0 rows affected (0.00 sec)Insert some records in the table using insert command −mysql> insert into DemoTable1971(StudentName, StudentPassword) values('John', '123456'); Query OK, 1 row affected (0.00 sec) mysql> insert into DemoTable1971(StudentName, StudentPassword) values('Chris', '123456'); Query OK, 1 row affected (0.00 sec) mysql> insert into DemoTable1971(StudentName, StudentPassword) values('David', '123456'); Query OK, 1 row affected (0.00 sec) mysql> insert into DemoTable1971(StudentName, StudentPassword) values('Mike', '123456'); Query OK, 1 row affected (0.00 sec)Display all ... Read More

Let us first create a table −mysql> create table DemoTable1969    (    BranchCode varchar(20)    ); Query OK, 0 rows affected (0.00 sec)Insert some records in the table using insert command −mysql> insert into DemoTable1969 values('CSE 101'); Query OK, 1 row affected (0.00 sec) mysql> insert into DemoTable1969 values('CSE 11'); Query OK, 1 row affected (0.00 sec) mysql> insert into DemoTable1969 values('CSE 15'); Query OK, 1 row affected (0.00 sec) mysql> insert into DemoTable1969 values('CSE 6'); Query OK, 1 row affected (0.00 sec) mysql> insert into DemoTable1969 values('CSE 201'); Query OK, 1 row affected (0.00 sec) mysql> insert into ... Read More

To set a specific value for only 1st three values, you need to use LIMIT 3. Let us first create a table −mysql> create table DemoTable1968    (    Id int NOT NULL AUTO_INCREMENT PRIMARY KEY,    Name varchar(20)    ); Query OK, 0 rows affected (0.00 sec)Insert some records in the table using insert command −mysql> insert into DemoTable1968(Name) values('Chris'); Query OK, 1 row affected (0.00 sec) mysql> insert into DemoTable1968(Name) values('David'); Query OK, 1 row affected (0.00 sec) mysql> insert into DemoTable1968(Name) values('Sam'); Query OK, 1 row affected (0.00 sec) mysql> insert into DemoTable1968(Name) values('Mike'); Query OK, 1 ... Read More

For this, you can use INSERT INTO SELECT statement along with LPAD(). Let us first create a table −mysql> create table DemoTable1967    (    Id int NOT NULL AUTO_INCREMENT PRIMARY KEY,    UserId varchar(20)    ); Query OK, 0 rows affected (0.00 sec)Insert some records in the table using insert command −mysql> insert into DemoTable1967(UserId)    select LPAD(COALESCE(MAX(id), 0) + 1, 3, '0') from DemoTable1967; Query OK, 1 row affected (0.00 sec) Records: 1  Duplicates: 0  Warnings: 0 mysql> insert into DemoTable1967(UserId)    select LPAD(COALESCE(MAX(id), 0) + 1, 3, '0') from DemoTable1967; Query OK, 1 row affected (0.00 sec) ... Read More

Let us first create a table −mysql> create table DemoTable1966    (    UserId int NOT NULL AUTO_INCREMENT PRIMARY KEY,    UserName varchar(20),    PhotoLiked int    ); Query OK, 0 rows affected (0.00 sec)Insert some records in the table using insert command −mysql> insert into DemoTable1966(UserName, PhotoLiked) values('Chris', 57); Query OK, 1 row affected (0.00 sec) mysql> insert into DemoTable1966(UserName, PhotoLiked) values('David', 100); Query OK, 1 row affected (0.00 sec) mysql> insert into DemoTable1966(UserName, PhotoLiked) values('Mike', 68); Query OK, 1 row affected (0.00 sec) mysql> insert into DemoTable1966(UserName, PhotoLiked) values('Sam', 78); Query OK, 1 row affected (0.00 sec)Display all ... Read More

To identify a column name, use INFORMATION_SCHEMA.COLUMNS in MySQL. Here’s the syntax −select table_name, column_name from INFORMATION_SCHEMA.COLUMNS where table_schema = SCHEMA() andcolumn_name='anyColumnName';Let us implement the above query in order to identify a column with its existence in all tables. Here, we are finding the existence of column EmployeeAge −mysql> select table_name, column_name    FROM INFORMATION_SCHEMA.COLUMNS    WHERE table_schema = SCHEMA()    AND column_name='EmployeeAge';This will produce the following output displaying the tables with specific column “EmployeeAge” −+---------------+-------------+ | TABLE_NAME    | COLUMN_NAME | +---------------+-------------+ | demotable1153 | EmployeeAge | | demotable1297 | EmployeeAge | | demotable1303 | EmployeeAge | | demotable1328 ... Read More