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Database Articles
Page 232 of 547
How to log in as a different user on MySQL?
If you want to login as a different user on MySQL, you need to use “mysql -u -p command”. The syntax is as follows to login as a different user.>mysql -u yourUsername -p After pressing enter key Enter password −To understand the above syntax, let us create a user in MySQL. The syntax is as follows −CREATE USER 'yourUserName'@'localhost' IDENTIFIED BY 'yourPassword';Now I am going to create a user with name ‘John’ and password is ‘john123456’. The query is as follows −mysql> CREATE USER 'John'@'localhost' IDENTIFIED BY 'john123456'; Query OK, 0 rows affected (0.15 sec)Now check the user has been ...
Read MoreSelect the topmost record from a table ordered by desc on the basis of ID?
For this, use ORDER BY DESC with LIMIT 1. Let us first create table −mysql> create table DemoTable -> ( -> Id int NOT NULL AUTO_INCREMENT PRIMARY KEY, -> UserName varchar(100), -> UserMessage text -> ); Query OK, 0 rows affected (1.17 sec)Insert some records in the table using insert command −mysql> insert into DemoTable(UserName, UserMessage) values('Adam', 'Hi'); Query OK, 1 row affected (0.92 sec) mysql> insert into DemoTable(UserName, UserMessage) values('Chris', 'Awesome'); Query OK, 1 row affected (0.52 sec) mysql> insert into DemoTable(UserName, UserMessage) values('Robert', 'Nice'); Query OK, 1 row affected (0.65 sec) ...
Read MoreHow to get the seed value of an identity column in MySQL?
For this, you can use SHOW VARIABLES command −mysql> SHOW VARIABLES LIKE 'auto_inc%';OutputThis will produce the following output −+--------------------------+-------+ | Variable_name | Value | +--------------------------+-------+ | auto_increment_increment | 1 | | auto_increment_offset | 1 | +--------------------------+-------+ 2 rows in set (0.95 sec)You can control over AUTO_INCREMENT outside.Let us first create a table −mysql> create table DemoTable -> ( -> StudentId int NOT NULL AUTO_INCREMENT PRIMARY KEY -> ); Query OK, 0 rows affected (0.94 sec)Insert some records in the table using insert command −mysql> insert into DemoTable ...
Read MoreCan we compare numbers in a MySQL varchar field?
Yes, we can do this by first using CAST(). Let us first create a table −mysql> create table DemoTable -> ( -> StudentId int NOT NULL AUTO_INCREMENT PRIMARY KEY, -> StudentScore varchar(100) -> ); Query OK, 0 rows affected (0.66 sec)Insert some records in the table using insert command −mysql> insert into DemoTable(StudentScore) values('90'); Query OK, 1 row affected (0.21 sec) mysql> insert into DemoTable(StudentScore) values('100'); Query OK, 1 row affected (0.13 sec) mysql> insert into DemoTable(StudentScore) values('56'); Query OK, 1 row affected (0.10 sec) mysql> insert into DemoTable(StudentScore) values('98'); Query OK, 1 ...
Read MoreMySQL select for exact case sensitive match with hyphen in records
For exact case sensitive match, use BINARY after WHERE clause in MySQL. Let us first create a table −mysql> create table DemoTable -> ( -> EmployeeCode varchar(100) -> ); Query OK, 0 rows affected (0.64 sec)Insert some records in the table using insert command −mysql> insert into DemoTable values('EMP-1122'); Query OK, 1 row affected (0.13 sec) mysql> insert into DemoTable values('emp-1122'); Query OK, 1 row affected (0.43 sec) mysql> insert into DemoTable values('EMP-6756'); Query OK, 1 row affected (0.19 sec) mysql> insert into DemoTable values('EMP-8775'); Query OK, 1 row affected (0.16 sec)Display all records ...
Read MoreWhat would be a query to remove nn from the text in MySQL?
To remove \r from the text, you need to use REPLACE command. The syntax is as follows −UPDATE yourTableName SET yourColumnName=REPLACE(yourColumnName, ’\r’, ’ ‘);To understand the above syntax, let us create a table. The query to create a table is as follows −mysql> create table removeDemo -> ( -> Id int NOT NULL AUTO_INCREMENT, -> Name text, -> PRIMARY KEY(Id) -> ); Query OK, 0 rows affected (0.79 sec)Now insert some records in the table using insert command. The query is as follows −mysql> insert into removeDemo(Name) values('John\rSmithCarol'); Query OK, 1 row affected (0.13 sec) mysql> insert into removeDemo(Name) values('LarryMike\rSam'); ...
Read MoreMySQL query to remove a value with only numbers in a column
For this, you can use REGEXP. Let us first create a table −mysql> create table DemoTable -> ( -> ClientCode varchar(100) -> ); Query OK, 0 rows affected (0.56 sec)Insert some records in the table using insert command −mysql> insert into DemoTable values('Chris902'); Query OK, 1 row affected (0.21 sec) mysql> insert into DemoTable values('Robert_'); Query OK, 1 row affected (0.14 sec) mysql> insert into DemoTable values('903'); Query OK, 1 row affected (0.15 sec) mysql> insert into DemoTable values('123_David'); Query OK, 1 row affected (0.21 sec)Display all records from the table using select statement ...
Read MoreCompare two tables and return missing ids in MySQL?
To compare two tables and return missing ids, you need to use a subquery. The syntax is as follows −SELECT yourFirstTableName.yourIdColumnName FROM yourFirstTableName WHERE NOT IN(SELECT yourSecondTableName.yourIdColumnName FROM youSecondTableName);To understand the above syntax, let us create a table with sample fields and then we will insert records. The query to create the first table −First_Tablemysql> create table First_Table -> ( -> Id int -> ); Query OK, 0 rows affected (0.88 sec)Now insert some records in the table using insert command. The query is as follows −mysql> insert into First_Table values(1); Query OK, 1 row affected (0.68 ...
Read MoreHow to convert string to time in MySQL?
You can use format specifier. Following is the syntax −select str_to_date(yourColumnName, '%d/%m/%Y %h:%i %p') as anyAliasName from yourTableName;Let us first create a table −mysql> create table DemoTable -> ( -> DueDate varchar(100) -> ); Query OK, 0 rows affected (0.51 sec)Insert some records in the table using insert command −mysql> insert into DemoTable values('11/02/2019 10:35'); Query OK, 1 row affected (0.20 sec) mysql> insert into DemoTable values('21/12/2018 12:01'); Query OK, 1 row affected (0.19 sec)Display all records from the table using select statement −mysql> select *from DemoTable;OutputThis will produce the following output −+------------------+ | DueDate ...
Read MoreHow to Order by a specific string in MySQL?
Let us first create a table −mysql> create table DemoTable -> ( -> FirstName varchar(100) -> ); Query OK, 0 rows affected (0.53 sec)Insert some records in the table using insert command −mysql> insert into DemoTable values('John'); Query OK, 1 row affected (0.13 sec) mysql> insert into DemoTable values('Adam'); Query OK, 1 row affected (0.17 sec) mysql> insert into DemoTable values('Sam'); Query OK, 1 row affected (0.22 sec) mysql> insert into DemoTable values('Johnny'); Query OK, 1 row affected (0.18 sec) mysql> insert into DemoTable values('Joy'); Query OK, 1 row affected (0.12 sec) ...
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