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Articles by Sharon Christine
Page 15 of 34
MySQL query to return the entire date and time based on a string and format
Let us first create a table −mysql> create table DemoTable -> ( -> AdmissionDate varchar(100) -> ); Query OK, 0 rows affected (0.66 sec)Insert some records in the table using insert command −mysql> insert into DemoTable values('Wed, 19 Jun 2019 04:10:20'); Query OK, 1 row affected (0.22 sec)Display all records from the table using select statement −mysql> select *from DemoTable;OutputThis will produce the following output −+---------------------------+ | AdmissionDate | +---------------------------+ | Wed, 19 Jun 2019 04:10:20 | +---------------------------+ 1 row in set (0.00 sec)Following is ...
Read MoreCreate a table named "select" in SQL databases?
Since “select” is a reserved word in MySQL, we cannot create a table name with it. But, if you still want to create such a table, surround the word select with quote.Let us first create a table −mysql> create table `select` -> ( -> Number int -> ); Query OK, 0 rows affected (0.79 sec)Insert some records in the table using insert command −mysql> insert into `select` values(10); Query OK, 1 row affected (0.16 sec) mysql> insert into `select` values(20); Query OK, 1 row affected (0.11 sec) mysql> insert into `select` values(30); Query OK, 1 row affected (0.12 ...
Read MoreHow to order an alphanumeric column in MySQL?
To order an alphanumeric column with values like “100X, “2Z”, etc. use the ORDER BY. Let us first create a table −mysql> create table DemoTable -> ( -> StudentId varchar(100) -> ); Query OK, 0 rows affected (0.52 sec)Insert some records in the table using insert command −mysql> insert into DemoTable values('2X'); Query OK, 1 row affected (0.21 sec) mysql> insert into DemoTable values('100Y'); Query OK, 1 row affected (0.20 sec) mysql> insert into DemoTable values('100X'); Query OK, 1 row affected (0.12 sec) mysql> insert into DemoTable values('2Z'); Query OK, 1 row affected (0.14 sec) mysql> ...
Read MoreHow to place number 0 from a column at the end maintaining the ascending search order in MySQL?
Let us first create a table −mysql> create table DemoTable -> ( -> Number int -> ); Query OK, 0 rows affected (0.58 sec)Insert some records in the table using insert command −mysql> insert into DemoTable values(9); Query OK, 1 row affected (0.13 sec) mysql> insert into DemoTable values(4); Query OK, 1 row affected (0.31 sec) mysql> insert into DemoTable values(0); Query OK, 1 row affected (0.13 sec) mysql> insert into DemoTable values(7); Query OK, 1 row affected (0.13 sec) mysql> insert into DemoTable values(11); Query OK, 1 row affected (0.12 sec)Display all ...
Read MoreFix Error with TYPE=HEAP for temporary tables in MySQL?
The TYPE=HEAP deprecated in newer MySQL versions. You can use ENGINE=HEAP instead of TYPE. Following is the syntax −ENGINE=HEAP;Let us first create a table. Here, we have set Engine=HEAP −mysql> create TEMPORARY table DemoTable -> ( -> StudentId int, -> StudentName varchar(30) -> )Engine = HEAP; Query OK, 0 rows affected (0.00 sec)Let us check the definition of table −mysql> show create table DemoTable;OutputThis will produce the following output −+--------------+-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+ | Table | Create Table | +--------------+-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+ | DemoTable | CREATE TEMPORARY TABLE `DemoTable` (`StudentId` int(11) DEFAULT NULL, `StudentName` varchar(30) COLLATE utf8_unicode_ci DEFAULT ...
Read MoreMySQL query to order by two fields and NULL values in chronological order?
Let us first create a table −mysql> create table DemoTable -> ( -> FirstName varchar(100), -> LastName varchar(100) -> ); Query OK, 0 rows affected (1.39 sec)Insert some records in the table using insert command −mysql> insert into DemoTable values('Sam', 'Brown'); Query OK, 1 row affected (0.25 sec) mysql> insert into DemoTable values(null, 'Smith'); Query OK, 1 row affected (0.16 sec) mysql> insert into DemoTable values('David', 'Taylor'); Query OK, 1 row affected (0.22 sec) mysql> insert into DemoTable values('Mike', null); Query OK, 1 row affected (0.45 sec)Display all records from the table using select statement −mysql> select ...
Read MoreMySQL DATE_ADD() to increment a date based on the value in another column?
Let us first create a table with one of the columns as DueDate and another one “RepeatTime, which displays how many times, let’s say a user was reminded to submit the payment −mysql> create table DemoTable -> ( -> DueDate date, -> RepeatTime int -> ); Query OK, 0 rows affected (0.57 sec)Insert some records in the table using insert command −mysql> insert into DemoTable values('2019-01-23', 3); Query OK, 1 row affected (0.13 sec) mysql> insert into DemoTable values('2019-06-22', 6); Query OK, 1 row affected (0.19 sec) mysql> insert into DemoTable values('2019-03-28', 2); Query ...
Read MoreChange a MySQL column to have NOT NULL constraint
To update the constraint, use the MODIFY command. Following is the syntax −alter table yourTableName modify yourExistingColumnName yourExistingDataType NOT NULL; Let us first create a table −mysql> create table DemoTable -> ( -> UserId int NOT NULL AUTO_INCREMENT, -> UserFirstName varchar(100), -> UserLastName varchar(100), -> UserEmailId varchar(100), -> UserPassword varchar(100), -> PRIMARY KEY(UserId) -> ); Query OK, 0 rows affected (0.91 sec)Following is the query to change the constraint of a column to NOT NULL −mysql> alter table DemoTable modify UserFirstName varchar(100) NOT NULL; Query OK, 0 rows affected (2.13 sec) Records: ...
Read MoreIs there a default ORDER BY value in MySQL?
There is no default ORDER BY value in MySQL. You need to specify ORDER BY clause explicitly. Following is the syntax −ORDER BY ASC; OR ORDER BY DESC;Let us first create a table −mysql> create table DemoTable -> ( -> StudentName varchar(100) -> ); Query OK, 0 rows affected (0.82 sec)Insert some records in the table using insert command −mysql> insert into DemoTable values('Sam'); Query OK, 1 row affected (0.11 sec) mysql> insert into DemoTable values('Chris'); Query OK, 1 row affected (0.14 sec) mysql> insert into DemoTable values('David'); Query OK, 1 row affected (0.15 sec) ...
Read MoreFetch a single ordered date from a column with MySQL LIMIT
To fetch a single date from a column, use “LIMIT 1. To order it, use ORDER BY clause. Let us first create a table −mysql> create table DemoTable -> ( -> DueDate varchar(100) -> ); Query OK, 0 rows affected (1.16 sec)Insert some records in the table using insert command −mysql> insert into DemoTable values('10-06-2019'); Query OK, 1 row affected (0.42 sec) mysql> insert into DemoTable values('01-12-2016'); Query OK, 1 row affected (0.52 sec) mysql> insert into DemoTable values('31-01-2018'); Query OK, 1 row affected (0.58 sec)Display all records from the table using select statement −mysql> select *from DemoTable;OutputThis ...
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