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Database Articles
Page 358 of 547
Select date from MySQL and format to text?
To select date and format, use SELECT DATE_FORMAT(). Following is the syntax −Syntaxselect date_format(yourColumnName, '%e %b %y') from yourTableName;Let us first create a table −mysql> create table DemoTable -> ( -> DueDate date -> ); Query OK, 0 rows affected (0.52 sec)Insert some records in the table using insert command −mysql> insert into DemoTable values('2019-01-11'); Query OK, 1 row affected (0.19 sec) mysql> insert into DemoTable values('2019-12-21'); Query OK, 1 row affected (0.13 sec) mysql> insert into DemoTable values('2019-09-15'); Query OK, 1 row affected (0.07 sec)Display all records from the table using select statement −mysql> select *from ...
Read MoreGroup MySQL rows in an array by column value?
To group rows in an array, use GROUP_CONCAT() along with the ORDER BY clause. Let us first create a table −mysql> create table DemoTable -> ( -> Id int, -> FirstName varchar(20) -> ); Query OK, 0 rows affected (0.78 sec)Insert some records in the table using insert command −mysql> insert into DemoTable values(101, 'John'); Query OK, 1 row affected (0.13 sec) mysql> insert into DemoTable values(102, 'Bob'); Query OK, 1 row affected (0.18 sec) mysql> insert into DemoTable values(101, 'David'); Query OK, 1 row affected (0.12 sec) mysql> insert into DemoTable values(101, 'Adam'); Query OK, ...
Read MoreGetting last value in MySQL group concat?
To get last value in group concat, use SUBSTRING_INDEX(). Let us first create a table −mysql> create table DemoTable1525 -> ( -> ListOfSubjects text -> ); Query OK, 0 rows affected (1.13 sec)Insert some records in the table using insert command −mysql> insert into DemoTable1525 values('MongoDB, C'); Query OK, 1 row affected (0.15 sec) mysql> insert into DemoTable1525 values('Java, C++, MySQL'); Query OK, 1 row affected (0.25 sec) mysql> insert into DemoTable1525 values('Python, C++, C, Java'); Query OK, 1 row affected (0.14 sec)Display all records from the table using select statement −mysql> select * from DemoTable1525;This will ...
Read MoreMatch the elements of an array in a MySQL query
Let us first create a table table −mysql> create table DemoTable1523 -> ( -> Id int, -> Value int -> ); Query OK, 0 rows affected (0.76 sec)Insert some records in the table using insert command −mysql> insert into DemoTable1523 values(1, 56); Query OK, 1 row affected (0.15 sec) mysql> insert into DemoTable1523 values(2, 78); Query OK, 1 row affected (0.15 sec) mysql> insert into DemoTable1523 values(1, 34); Query OK, 1 row affected (0.10 sec) mysql> insert into DemoTable1523 values(2, 45); Query OK, 1 row affected (0.17 sec) mysql> insert into DemoTable1523 values(1, 99); Query OK, ...
Read MoreSum columns corresponding values according to similar dates in MySQL?
For this, use aggregate function SUM() along with GROUP BY. Let us first create a table −mysql> create table DemoTable1522 -> ( -> ProductPurchaseDate date, -> NumberOfProduct int -> ); Query OK, 0 rows affected (1.51 sec)Insert some records in the table using insert command −mysql> insert into DemoTable1522 values('2019-01-21', 45); Query OK, 1 row affected (0.14 sec) mysql> insert into DemoTable1522 values('2018-12-31', 78); Query OK, 1 row affected (0.12 sec) mysql> insert into DemoTable1522 values('2019-01-21', 67); Query OK, 1 row affected (0.12 sec) mysql> insert into DemoTable1522 values('2019-03-01', 56); Query OK, 1 row affected (0.19 ...
Read MoreUpdate a column in MySQL and remove the trailing underscore values
To remove the trailing values, use TRIM() as in the below update syntax −update yourTableName set yourColumnName=trim(trailing '_' from yourColumnName);Let us first create a table −mysql> create table DemoTable1521 -> ( -> StudentCode varchar(20) -> ); Query OK, 0 rows affected (1.33 sec)Insert some records in the table using insert command −mysql> insert into DemoTable1521 values('345_'); Query OK, 1 row affected (0.19 sec) mysql> insert into DemoTable1521 values('12345'); Query OK, 1 row affected (0.38 sec) mysql> insert into DemoTable1521 values('9084_'); Query OK, 1 row affected (1.29 sec)Display all records from the table using select statement −mysql> select ...
Read MoreHow do I select data from one table only where column values from that table match the column values of another table in MySQL?
For this, you can use subquery along with EXISTS. Let us first create a table −mysql> create table DemoTable1 -> ( -> Id int, -> SubjectName varchar(20) -> ); Query OK, 0 rows affected (0.58 sec)Insert some records in the table using insert command −mysql> insert into DemoTable1 values(111, 'MySQL'); Query OK, 1 row affected (0.12 sec) mysql> insert into DemoTable1 values(112, 'MongoDB'); Query OK, 1 row affected (0.15 sec) mysql> insert into DemoTable1 values(113, 'Java'); Query OK, 1 row affected (0.17 sec) mysql> insert into DemoTable1 values(114, 'C'); Query OK, 1 row affected (0.27 sec) ...
Read MoreMySQL query to select rows one batch at a time
For this, you can use the concept of LIMIT and OFFSET. Let us first create a table −mysql> create table DemoTable1514 -> ( -> Id int NOT NULL AUTO_INCREMENT PRIMARY KEY, -> FirstName varchar(20) -> ); Query OK, 0 rows affected (0.63 sec)Insert some records in the table using insert command −mysql> insert into DemoTable1514(FirstName) values('Chris'); Query OK, 1 row affected (0.17 sec) mysql> insert into DemoTable1514(FirstName) values('Bob'); Query OK, 1 row affected (0.12 sec) mysql> insert into DemoTable1514(FirstName) values('Sam'); Query OK, 1 row affected (0.08 sec) mysql> insert into DemoTable1514(FirstName) values('Mike'); Query OK, 1 row ...
Read MoreWhen inserting a new row, should I include the columns that are null in the MySQL query?
If you do not specify the column list in insert statement then you can use below syntax −insert into yourTableName values(NULL, yourValue, NULL, NULL, .....N);Let us first create a table −mysql> create table DemoTable1513 -> ( -> StudentId int, -> StudentName varchar(20) , -> StudentAge int, -> StudentCountryName varchar(20) -> ); Query OK, 0 rows affected (0.58 sec)Insert some records in the table using insert command −mysql> insert into DemoTable1513 values(NULL, 'Chris Brown', NULL, NULL); Query OK, 1 row affected (0.11 sec) mysql> insert into DemoTable1513 values(101, NULL, NULL, NULL); Query OK, 1 row ...
Read MoreHow do I detect if the ON UPDATE event fired with query in MySQL?
You can detect with the help of row_count(). If the row_count() returns 1 that means it is a new record. If it returns 2, that means the ON UPDATE event is fired with query. Following is the syntax −select row_count();Let us first create a table −mysql> create table DemoTable1512 -> ( -> Value int , -> UNIQUE(Value) -> ); Query OK, 0 rows affected (0.60 sec)Insert some records in the table using insert command −mysql> insert into DemoTable1512 values(90) on duplicate key update Value=Value+10; Query OK, 1 row affected (0.09 sec)Now you can check the on ...
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