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MySQL Articles
Page 275 of 355
Can MySQL concatenate strings with ||?
Yes, you can concatenate strings with || in MySQL with the help of sql_mode. Set the sql_mode to PIPES_AS_CONCAT.The syntax is as followsset sql_mode=PIPES_AS_CONCAT;The following is the syntax to concat with the help of ||.SELECT ‘yourValue' || yourColumName AS anyAliasName FROM yourTableName;To understand the above syntax, let us create a table. The query to create a table is as followsmysql> create table PipeConcatDemo - > ( - > Name varchar(20) - > ); Query OK, 0 rows affected (0.93 sec)Insert some records in the table using insert command.The query is as followsmysql> insert into PipeConcatDemo values('Larry'); Query ...
Read MoreRun SQL file in MySQL database from terminal?
To run SQL file in database, you need to use below syntax:mysql -u yourUserName -p yourDatabaseName < yourFileName.sqlTo understand the above syntax, let us open command prompt using windows+R shortcut key.The snapshot is as follows:After pressing OK button, you will get a command prompt. The snapshot is as follows:Now reach the bin directory, the snapshot is as follows:Here is my file ‘mydb.sql’ which is located in bin directory. The snapshot and content of SQL file is as follows:Now you can type the above syntax which I have discussed to run SQL file. The snapshot of command is as follows:Now you ...
Read MoreHow to add a “created at” column in a table to set the timestamp in MySQL?
You need to use ALTER command to add a created at column to an already created table in MySQL.Let us first create a table. The query to create a table is as follows. Here is your table without the “created at” columnmysql> create table formDemo - > ( - > Id int NOT NULL AUTO_INCREMENT PRIMARY KEY, - > Email varchar(128), - > PhoneNumber varchar(15), - > Country varchar(30), - > Platform varchar(40) - > ); Query OK, 0 ...
Read MoreMySQL case-insensitive DISTINCT?
If you want case-insensitive distinct, you need to use UPPER() or LOWER().Case 1: Using UPPER().The syntax is as follows:SELECT DISTINCT UPPER(yourColumnName) FROM yourTableName;Case 2: Using LOWER().The syntax is as follows:SELECT DISTINCT LOWER(yourColumnName) FROM yourTableName;To understand the above syntax, let us create a table. The query to create a table is as follows:mysql> create table CaseInsensitiveDistinctDemo -> ( -> Id int NOT NULL AUTO_INCREMENT, -> UserEmailId varchar(30), -> UserPassword varchar(10), -> PRIMARY KEY(Id) -> ); Query OK, 0 rows affected (0.64 sec)Now you ...
Read MoreHow to fix the incorrect datetime value while inserting in a MySQL table?
To avoid the incorrect datetime value error, you can use the STR_TO_DATE() method.As we know the datetime format is YYYY-MM-DD and if you won’t insert in the same format, the error would get generated.Let us see what actually lead to this error. For this, let us create a new table. The query to create a table is as followsmysql> create table CorrectDatetimeDemo - > ( - > Id int NOT NULL AUTO_INCREMENT PRIMARY KEY, - > ArrivalTime datetime - > ); Query OK, 0 rows affected (0.63 sec)The occurs when we try to include a ...
Read MoreImplement MySQL INSERT MAX()+1?
You need to use COALESCE() function for this. The syntax is as follows:INSERT INTO yourTableName(yourColumnName1, yourColumnName2) SELECT 1 + COALESCE((SELECT MAX(yourColumnName1) FROM yourTableName WHERE yourColumnName2=’yourValue’), 0), ’yourValue’;To understand the above syntax, let us create a table. The query to create a table is as follows:mysql> create table InsertMaxPlus1Demo -> ( -> Id int, -> Name varchar(20) -> ); Query OK, 0 rows affected (1.27 sec)Now you can insert some records in the table using insert command. The query is as follows:mysql> insert into InsertMaxPlus1Demo(Id, Name) values(1, 'John'); Query OK, 1 row affected (0.12 sec) mysql> insert ...
Read MoreHow to increment all the rows of a particular column by 1 in a single MySQL query (ID column +1)?
To increment all the rows of a particular ID column by 1, you need to use UPDATE command and update the table. The syntax of the query is as follows. We have also used ORDER BY hereUPDATE yourTableName SET yourIdColumnName=yourIdColumnName+1 ORDER BY yourIdColumnName DESC;To understand the above syntax, let us create a table. The query to create a table is as followsmysql> create table IdColumnadd1Demo - > ( - > Id int NOT NULL AUTO_INCREMENT PRIMARY KEY - > ); Query OK, 0 rows affected (0.58 sec)Insert some records in the ...
Read MoreHow to add the JDBC MySQL driver to an Eclipse project?
To add the JDBC MySQL driver to an Eclipse project, you need to follow the below steps.The first step is as follows:Step1: Create a dynamic web project with some name in Eclipse.Step2: After pressing the Dynamic Web Project, a new window will open. Now give the project name. The screenshot is as follows:After clicking the Finish button, you will get a project structure. The screenshot is as follows:Therefore, I have a project name JDBCJarFiles and in WEB-INF, there is a lib folder. You can add JDBC jar files in lib folder. Now, paste the jar files here. The screenshot is as ...
Read MoreWhere is the MySQL database gets saved when it is created?
If you want the database location i.e. where it is created in MySQL, you can use system variable @@datadir.The syntax is as followsSELECT @@datadir;The following is the querymysql> select @@datadir;Here is the output. The above query returns the location+---------------------------------------------+ | @@datadir | +---------------------------------------------+ | C:\ProgramData\MySQL\MySQL Server 8.0\Data\ | +---------------------------------------------+ 1 row in set (0.00 sec)Now reach the above directory in your system. The screenshot of the ...
Read MoreCan we select row by DATEPART() in MySQL? Is it possible?
There is no DATEPART() function in MySQL, you need to use MONTH() function to extract the month name from date column. The syntax is as follows:SELECT *FROM yourTableName WHERE MONTH(yourDateColumnName)=yourValue;To understand the above syntax, let us create a table. The query to create a table is as follows:mysql> create table SelectRowFromDatePart -> ( -> Id int NOT NULL AUTO_INCREMENT, -> LoginDate date, -> PRIMARY KEY(Id) -> ); Query OK, 0 rows affected (2.42 sec)Now you can insert some records in the table using ...
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