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Articles on Trending Technologies
Technical articles with clear explanations and examples
MySQL multiple COUNT with multiple columns?
You can use an aggregate function SUM() along with IF(). Let us first create a table −mysql> create table DemoTable ( FirstName varchar(100), LastName varchar(100) ); Query OK, 0 rows affected (2.80 sec)Insert some records in the table using insert command −mysql> insert into DemoTable values('Adam', 'Smith'); Query OK, 1 row affected (0.25 sec) mysql> insert into DemoTable values('John', 'Smith'); Query OK, 1 row affected (0.36 sec) mysql> insert into DemoTable values('John', 'Doe'); Query OK, 1 row affected (1.38 sec) mysql> insert into DemoTable values('Bob', 'Doe'); Query OK, 1 row affected (0.16 sec) mysql> insert into DemoTable values('Sam', ...
Read MoreUse LIKE % to fetch multiple values in a single MySQL query
To fetch multiple values wit LIKE, use the LIKE operator along with OR operator. Let us first create a table −mysql> create table DemoTable1027 ( Id int, Name varchar(100) ); Query OK, 0 rows affected (1.64 sec)Insert some records in the table using insert command −mysql> insert into DemoTable1027 values(100, 'John'); Query OK, 1 row affected (0.72 sec) mysql> insert into DemoTable1027 values(20, 'Chris'); Query OK, 1 row affected (0.56 sec) mysql> insert into DemoTable1027 values(200, 'Robert'); Query OK, 1 row affected (0.84 sec) mysql> insert into DemoTable1027 values(400, 'Mike'); Query OK, 1 row affected (0.47 sec)Display all ...
Read MoreMySQL select query to fetch data with null value?
Let us first create a table −mysql> create table DemoTable ( CustomerName varchar(100), CustomerCountryName varchar(100) ); Query OK, 0 rows affected (0.95 sec)Insert some records in the table using insert command −mysql> insert into DemoTable values('Chris', 'US'); Query OK, 1 row affected (0.18 sec) mysql> insert into DemoTable values('Bob', 'UK'); Query OK, 1 row affected (0.10 sec) mysql> insert into DemoTable values('Carol', NULL); Query OK, 1 row affected (0.13 sec) mysql> insert into DemoTable values('David', 'AUS'); Query OK, 1 row affected (0.32 sec) mysql> insert into DemoTable values('Mike', NULL); Query OK, 1 row affected (0.18 sec)Display all records ...
Read MoreShow column value twice in MySQL Select?
You can use concat(). Let us first create a table −mysql> create table DemoTable ( Value int ); Query OK, 0 rows affected (0.73 sec)Insert some records in the table using insert command −mysql> insert into DemoTable values(100); Query OK, 1 row affected (0.18 sec) mysql> insert into DemoTable values(200); Query OK, 1 row affected (0.08 sec) mysql> insert into DemoTable values(100); Query OK, 1 row affected (0.11 sec) mysql> insert into DemoTable values(200); Query OK, 1 row affected (0.10 sec) mysql> insert into DemoTable values(200); Query OK, 1 row affected (0.11 sec) mysql> insert into DemoTable values(100); Query ...
Read MoreGet count of zeros for columns values declared with INT type in MySQL
For this, you can use LENGTH() along with REPLACE(). Let us first create a table −mysql> create table DemoTable ( Value int ); Query OK, 0 rows affected (1.22 sec)Insert some records in the table using insert command −mysql> insert into DemoTable values(10002000); Query OK, 1 row affected (0.09 sec) mysql> insert into DemoTable values(00000); Query OK, 1 row affected (0.17 sec) mysql> insert into DemoTable values(400560); Query OK, 1 row affected (0.19 sec)Display all records from the table using select statement −mysql> select *from DemoTable;This will produce the following output −+----------+ | Value | +----------+ | 10002000 ...
Read MoreReturn value from a row if it is NOT NULL, else return the other row value in another column with MySQL
For this, you can use IFNULL(). Let us first create a table −mysql> create table DemoTable ( FirstName varchar(100), LastName varchar(100) ); Query OK, 0 rows affected (0.62 sec)Insert some records in the table using insert command −mysql> insert into DemoTable values('John', 'Doe'); Query OK, 1 row affected (0.29 sec) mysql> insert into DemoTable values(NULL, 'Taylor'); Query OK, 1 row affected (0.12 sec) mysql> insert into DemoTable values('David', NULL); Query OK, 1 row affected (0.15 sec) mysql> insert into DemoTable values(NULL, 'Miller'); Query OK, 1 row affected (0.12 sec)Display all records from the table using select statement −mysql> ...
Read MoreMySQL query to compare and display only the rows with NULL values
For this, you can use IFNULL(). Let us first create a table −mysql> create table DemoTable ( Value1 int, Value2 int ); Query OK, 0 rows affected (0.75 sec)Insert some records in the table using insert command −mysql> insert into DemoTable values(10, NULL); Query OK, 1 row affected (0.10 sec) mysql> insert into DemoTable values(20, 40); Query OK, 1 row affected (0.27 sec) mysql> insert into DemoTable values(3, NULL); Query OK, 1 row affected (0.20 sec)Display all records from the table using select statement −mysql> select *from DemoTable;This will produce the following output −+--------+--------+ | Value1 | Value2 ...
Read MoreMySQL UNIQUE declaration to avoid inserting duplicate values?
Following is the declaration for a UNIQUE clause in MySQL −create table yourTableName ( yourColumnName1 dataType, yourColumnName2 dataType, UNIQUE(yourColumnName1), UNIQUE(yourColumnName1) );Let us first create a table −mysql> create table DemoTable ( Value int, Value2 int, UNIQUE(Value), UNIQUE(Value2) ); Query OK, 0 rows affected (13.98 sec)Insert some records in the table using insert command. Here, duplicate records won’t insert because we have used UNIQUE above −mysql> insert into DemoTable values(10, 20) ; Query OK, 1 row affected (0.32 sec) mysql> insert into DemoTable values(10, 30); ERROR 1062 (23000): Duplicate entry '10' for key ...
Read MoreDisplay distinct dates in MySQL from a column with date records
Let us first create a table −mysql> create table DemoTable ( AdmissionDate datetime ); Query OK, 0 rows affected (8.99 sec)Insert some records in the table using insert command −mysql> insert into DemoTable values('2010-01-10 12:30:45'); Query OK, 1 row affected (0.14 sec) mysql> insert into DemoTable values('2010-01-10 12:30:45'); Query OK, 1 row affected (0.46 sec) mysql> insert into DemoTable values('2010-01-10 12:30:45'); Query OK, 1 row affected (0.71 sec) mysql> insert into DemoTable values('2010-01-12 12:30:45'); Query OK, 1 row affected (1.22 sec) mysql> insert into DemoTable values('2010-01-20 12:30:45'); Query OK, 1 row affected (0.19 sec) mysql> insert into DemoTable values('2010-01-20 ...
Read MoreCheck if a number is Palindrome in PL/SQLs
In this section we will see how to check whether a number is Palindrome or not using the PL/SQL. In PL/SQL code, some group of commands are arranged within a block of related declaration of statements.A number is palindrome if the number, and the reverse of that number are same. Suppose a number 12321, this is palindrome, but 12345 is not a palindrome.ExampleDECLARE n number; m number; temp number:=0; rem number; BEGIN n :=12321; m :=n; while n>0 loop rem := mod(n, 10); temp := (temp*10)+rem; ...
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