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Articles on Trending Technologies
Technical articles with clear explanations and examples
MySQL query to return TRUE for rows having positive value?
To return TRUE for positive values and FALSE for negative, use MySQL IF(). Let us first create a table −mysql> create table DemoTable2038 -> ( -> Id int NOT NULL AUTO_INCREMENT PRIMARY KEY, -> Value int -> ); Query OK, 0 rows affected (0.87 sec)Insert some records in the table using insert command −mysql> insert into DemoTable2038(Value) values(57); Query OK, 1 row affected (0.18 sec) mysql> insert into DemoTable2038(Value) values(-100);; Query OK, 1 row affected (0.12 sec) mysql> insert into DemoTable2038(Value) values(-78); Query OK, 1 row affected (0.42 sec) mysql> insert into DemoTable2038(Value) ...
Read MoreFetch the first letter of a column value and insert it in another column with MySQL
For this, use the concept of LEFT() function. Let us first create a table −mysql> create table DemoTable2036 -> ( -> FirstLetter varchar(20), -> Title varchar(20) -> ); Query OK, 0 rows affected (1.01 sec)Insert some records in the table using insert command −mysql> insert into DemoTable2036(Title) values('Chris'); Query OK, 1 row affected (0.14 sec) mysql> insert into DemoTable2036(Title) values('John'); Query OK, 1 row affected (0.10 sec) mysql> insert into DemoTable2036(Title) values('Adam'); Query OK, 1 row affected (0.15 sec)Display all records from the table using select statement −mysql> select *from DemoTable2036;This will produce the ...
Read MoreValidate Date in MySQL using a custom function
Let us create a custom function to validate date in MySQL −mysql> set global log_bin_trust_function_creators=1; Query OK, 0 rows affected (0.03 sec) mysql> delimiter // mysql> create function isValidDate(actualDate varchar(255)) returns int -> begin -> declare flag int; -> if (select length(date(actualDate)) IS NOT NULL ) then -> set flag = 1; -> else -> set flag = 0; -> end if; -> return flag; -> end -> // Query OK, 0 rows affected (0.11 sec) mysql> delimiter ;Case 1 −When parameter is null value i.e. the date to be ...
Read MoreDisplay TRUE FALSE records as 0 1 in MySQL
Set the column as BOOLEAN to display 0 and 1 values. Let us create a table −mysql> create table DemoTable2035 -> ( -> Id int NOT NULL AUTO_INCREMENT, -> Name varchar(20), -> isMarried boolean, -> PRIMARY KEY(Id) -> ); Query OK, 0 rows affected (0.72 sec)Insert some records in the table using insert command −mysql> insert into DemoTable2035(Name, isMarried) values('Chris', true); Query OK, 1 row affected (0.10 sec) mysql> insert into DemoTable2035(Name, isMarried) values('David', false); Query OK, 1 row affected (0.08 sec) mysql> insert into DemoTable2035(Name, isMarried) values('Bob', true); Query OK, 1 ...
Read MoreImplement Dynamic SQL query inside a MySQL stored procedure?
For dynamic SQL query in a stored procedure, use the concept of PREPARE STATEMENT. Let us first create a table −mysql> create table DemoTable2033 -> ( -> Id int NOT NULL AUTO_INCREMENT PRIMARY KEY, -> Name varchar(20) -> ); Query OK, 0 rows affected (1.61 sec)Insert some records in the table using insert command −mysql> insert into DemoTable2033(Name) values('Chris'); Query OK, 1 row affected (0.85 sec) mysql> insert into DemoTable2033(Name) values('Bob'); Query OK, 1 row affected (0.19 sec) mysql> insert into DemoTable2033(Name) values('David'); Query OK, 1 row affected (0.24 sec) mysql> insert into ...
Read MoreHow to reset the JShell session in Java 9?
Java 9 has introduced JShell for Java, and it allows us to evaluate code snippets such as declarations, statements, and expressions.During the JShell session, we need to reset it without closing and re-opening JShell then we can use the internal command: "/reset". By using this command, code entered during the current session has erased. It can be useful when we want to test new classes, create new variables, etc. while keeping the names previously used.In the below snippet, we have created variables x, y, and str. We can able to see all entered code snippets using the "/list" command. After that, we can apply ...
Read MoreWhat are the different feedback modes in JShell in Java 9?
When performing an operation in the JShell tool, it displays a message in return (success of the command, error, and type of a variable created as well as its value). It has been customized using the command: "/set feedback". This command displays the type of return currently configured as well as the different return modes available.jshell> /set feedback | /set feedback normal | | Available feedback modes: | concise | normal | silent | verboseThere are four feedback modes available in JShell as listed below:1) /set feedback normal: This is the default JShell feedback. When we evaluate an expression, JShell ...
Read MoreCalculating byte values to megabyte (MB) in MySQL?
Here, we are taking BIGINT type, since it takes 8 byte signed integer. Let us first create a table with column as BIGINT type −mysql> create table DemoTable2031 -> ( -> ByteValue bigint -> ); Query OK, 0 rows affected (1.17 sec)Insert some records in the table using insert command −mysql> insert into DemoTable2031 values(1048576); Query OK, 1 row affected (0.14 sec) mysql> insert into DemoTable2031 values(1073741824); Query OK, 1 row affected (0.13 sec)Display all records from the table using select statement −mysql> select *from DemoTable2031;This will produce the following output −+------------+ | ByteValue | ...
Read MoreFind maximum value from a VARCHAR column in MySQL
To find maximum value, use MAX() along with CAST(), since the values are of VARCHAR type. Let us first create a table −mysql> create table DemoTable2030 -> ( -> Value varchar(20) -> ); Query OK, 0 rows affected (0.44 sec)Insert some records in the table using insert command −mysql> insert into DemoTable2030 values('8'); Query OK, 1 row affected (0.14 sec) mysql> insert into DemoTable2030 values('1'); Query OK, 1 row affected (0.19 sec) mysql> insert into DemoTable2030 values('10001'); Query OK, 1 row affected (0.11 sec) mysql> insert into DemoTable2030 values('901'); Query OK, 1 row affected ...
Read MoreUpdate the content of a specific cell in MySQL
Let us first create a table −mysql> create table DemoTable2029 -> ( -> Id int, -> FirstName varchar(20), -> LastName varchar(20) -> ); Query OK, 0 rows affected (0.98 sec)Insert some records in the table using insert command −mysql> insert into DemoTable2029 values(1, 'Chris', 'Brown') -> ; Query OK, 1 row affected (0.13 sec) mysql> insert into DemoTable2029 values(2, 'David', 'Miller'); Query OK, 1 row affected (0.12 sec) mysql> insert into DemoTable2029 values(3, 'John', 'Smith'); Query OK, 1 row affected (0.20 sec) mysql> insert into DemoTable2029 values(4, 'John', 'Brown'); Query OK, 1 ...
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