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MySQL Articles
Page 340 of 355
Find rows where column value ends with a specific substring in MySQL?
To find rows and update with new value where column value ends with specific substring you need to use LIKE operator.The syntax is as follows:UPDATE yourTableName SET yourColumnName=’yourValue’ WHERE yourColumnName LIKE ‘%.yourString’;To understand the above syntax, let us create a table. The query to create a table is as follows:mysql> create table RowEndsWithSpecificString -> ( -> Id int NOT NULL AUTO_INCREMENT, -> FileName varchar(30), -> PRIMARY KEY(Id) -> ); Query OK, 0 rows affected (1.50 sec)Now you can insert some records in the table using ...
Read MoreSearch for text between delimiters in MySQL?
You need to use LOCATE() along with SUBSTR(). The below syntax will find the word after delimiter. Here, delimiter is colon(:), you can use another i.e. it is up to you. The syntax is as follows −SELECT SUBSTR(yourColumnName, LOCATE(':', yourColumnName)+1, (CHAR_LENGTH(yourColumnName) - LOCATE(':', REVERSE(yourColumnName)) - LOCATE(':', yourColumnName))) AS anyAliasName FROM yourTableName;To understand the above syntax, let us create a table. The query to create a table is as follows −mysql> create table SearchTextBetweenDelimitersDemo -> ( -> ...
Read MoreSorting a VARCHAR column as FLOAT using the CAST operator isn’t working in MySQL ?
If your cast does not work, then you can use yourColumnName*1 with ORDER BY clause.Using yourColumnName*1. The syntax is as follows:SELECT yourColumnName1, yourColumnName2, ...N FROM yourTableName ORDER BY yourColumnName*1 DESC;You can also use CAST() operator. The syntax is as follows:SELECT yourColumnName1, yourColumnName2, ...N FROM yourTableName ORDER BY CAST(yourColumnName as DECIMAL(8, 2)) DESC;To understand the above syntax, let us create a table. The query to create a table is as follows:mysql> create table VarcharColumnAsFloatDemo -> ( -> Id int NOT NULL AUTO_INCREMENT, -> Amount varchar(20), -> PRIMARY KEY(Id) ...
Read MoreEmpty string in not-null column in MySQL?
In PHP, the empty string equals to a NULL value, but in MySQL, the case is the different i.e. empty string is not equal to NULL value. To understand the above syntax, let us create a column with NOT NULL constraint while you can insert an empty string.Let us create a table. The query to create a table is as follows −mysql> create table EmptyStringNotNullDemo -> ( -> Id int NOT NULL AUTO_INCREMENT, -> Name varchar(10) not null, -> PRIMARY KEY(Id) -> ); Query OK, 0 rows affected (0.83 sec)Now you can insert some records ...
Read MoreResolve an error whenever multiple rows are returned in MySQL Benchmark?
You will get an error whenever you return multiple rows in the benchmark. Return a scalar value or single row instead of multiple rows. The syntax is as follows −SELECT yourColumnName FROM yourTableName WHERE yourCondition.To understand the above syntax, let us create a table. The query to create a table is as follows −mysql> create table UserDemo -> ( -> UserId int, -> UserName varchar(20), -> RegisteredCourse varchar(10) -> ); Query OK, 0 rows affected (0.67 sec)Insert some records in the table using insert command. The query is as follows −mysql> insert into UserDemo values(1, ...
Read MoreMySQL- GROUP and COUNT by date?
You can use GROUP BY clause and COUNT() function for this. The syntax is as follows −SELECT yourColumnName1, yourColumnName2, ..N, COUNT(*) as anyAliasName FROM yourTableName GROUP BY yourColumnName1, yourColumnName2;To understand the above syntax, let us create a table. The query to create a table is as follows −mysql> create table GroupAndCountByDate -> ( -> Id int NOT NULL AUTO_INCREMENT, -> TripDate date, -> ShopId int, -> PRIMARY KEY(Id) -> ); Query OK, 0 rows affected (0.79 sec)Now you can insert some records in the table using insert command. The query is as follows −mysql> ...
Read MoreReturn order of MySQL SHOW COLUMNS?
To return order of MySQL SHOW COLUMNS, you need to use ORDER BY clause. The syntax is as follows −SELECT COLUMN_NAME FROM INFORMATION_SCHEMA.COLUMNS WHERE table_name = ‘yourTableName’ AND column_name LIKE 'yourStartColumnName%' ORDER BY column_name DESC;Let us create a table in database TEST. The query to create a table is as follows −mysql> create table OrderByColumnName -> ( -> StudentId int, -> StudentFirstName varchar(10), -> StudentLastName varchar(10), -> StudentAddress varchar(20), -> StudentAge int, -> StudentMarks int ...
Read MoreMySQL Query to get count of unique values?
To count the unique values on a column, you need to use keyword DISTINCT. To understand how it is done, let us create a table. The query to create a table is as follows −mysql> create table UniqueCountByIPAddress -> ( -> Id int NOT NULL AUTO_INCREMENT, -> UserHits int, -> UserIPAddress varchar(50), -> PRIMARY KEY(Id) -> ); Query OK, 0 rows affected (0.69 sec)Insert some records in the table using insert command. The query is as follows −mysql> insert into UniqueCountByIPAddress(UserHits, UserIPAddress) values(10, '127.0.0.1'); Query OK, 1 row affected (0.20 sec) mysql> insert into ...
Read MoreShould I store a field PRICE as an int or as a float in the database?
You do not need to store a field PRICE as an int or as float in the database. For this, you can set the DECIMAL()..Most of the time integers can be used to represent the float point numbers and these integers are internally cast into DECIMAL() data type. Therefore, if you have field PRICE then always use DECIMAL() data type. The syntax is as follows −DECIMAL(M, D);Here, M represents the ‘TotalNumberOfDigit’ and D represents the ‘Number OfDigitAfterDecimalPoint’.To understand the above concept, let us create a table with field PRICE as DECIMAL data type. The query is as follows −mysql> create ...
Read MoreMySQL how to declare a datetime variable?
To declare a datetime variable, you need to use a user-defined variable using the SET command. The syntax is as follows −SET @anyVariableName=’yourdatetimeValue’;To understand the above syntax, let us create a table. The query to create a table is as follows −mysql> create table datetimeVariables -> ( -> Id int NOT NULL AUTO_INCREMENT, -> Name varchar(10), -> ArrivalDatetime datetime, -> PRIMARY KEY(Id) -> ); Query OK, 0 rows affected (0.78 sec)Insert some records in the table using insert command. The query to ...
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