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MySQL Articles
Page 138 of 355
Display custom text in a new column on the basis of null values in MySQL?
Let us first create a table −mysql> create table DemoTable1953 ( StudentName varchar(20) ); Query OK, 0 rows affected (0.00 sec)Insert some records in the table using insert command −mysql> insert into DemoTable1953 values('Chris'); Query OK, 1 row affected (0.00 sec) mysql> insert into DemoTable1953 values(NULL); Query OK, 1 row affected (0.00 sec) mysql> insert into DemoTable1953 values('David'); Query OK, 1 row affected (0.00 sec) mysql> insert into DemoTable1953 values(NULL); Query OK, 1 row affected (0.00 sec)Display all records from the table using select statement −mysql> select * from DemoTable1953;This will produce the following output −+-------------+ | ...
Read MoreSplit float value in two columns of a MySQL table?
To split float value in two columns, the first column will have a value before decimal. The second column will have a value after decimal. For this, you can use SUBSTRING_INDEX() along with CAST(). Let us first create a table −mysql> create table DemoTable1951 ( Value1 varchar(20) ); Query OK, 0 rows affected (0.00 sec)Insert some records in the table using insert command −mysql> insert into DemoTable1951 values('100.50'); Query OK, 1 row affected (0.00 sec) mysql> insert into DemoTable1951 values('70.90'); Query OK, 1 row affected (0.00 sec) mysql> insert into DemoTable1951 values('1000.55'); Query OK, 1 row affected ...
Read MoreCombine SUM and FORMAT in MySQL to format the result
Let us create a table −mysql> create table DemoTable1950 ( Amount float ); Query OK, 0 rows affected (0.00 sec)Insert some records in the table using insert command −mysql> insert into DemoTable1950 values(45.60); Query OK, 1 row affected (0.00 sec) mysql> insert into DemoTable1950 values(101.78); Query OK, 1 row affected (0.00 sec) mysql> insert into DemoTable1950 values(75.90); Query OK, 1 row affected (0.00 sec) mysql> insert into DemoTable1950 values(89.45); Query OK, 1 row affected (0.00 sec)Display all records from the table using select statement −mysql> select * from DemoTable1950;This will produce the following output −+--------+ | Amount ...
Read MoreSet NOT NULL attribute to an existing column in MySQL
To set NOT NULL attribute to an existing column, use ALTER TABLE command. Let us first create a table −mysql> create table DemoTable1949 ( UserId int, UserName varchar(20) ); Query OK, 0 rows affected (0.00 sec)Here is the query to set NOT NULL attribute to an existing column −mysql> alter table DemoTable1949 modify UserName varchar(20) not null; Query OK, 0 rows affected (0.00 sec) Records: 0 Duplicates: 0 Warnings: 0Let us check the description of table −mysql> desc DemoTable1949;This will produce the following output −+----------+-------------+------+-----+---------+-------+ | Field | Type | Null | ...
Read MoreSort only numbers from alphanumeric string in MySQL?
To sort only numbers from alphanumeric string, use ORDER BY RIGHT(). Let us first create a table −mysql> create table DemoTable1948 ( StudentCode varchar(20) ); Query OK, 0 rows affected (0.00 sec)Insert some records in the table using insert command −mysql> insert into DemoTable1948 values('121John_567'); Query OK, 1 row affected (0.00 sec) mysql> insert into DemoTable1948 values('Adam_101'); Query OK, 1 row affected (0.00 sec) mysql> insert into DemoTable1948 values('Bob_563'); Query OK, 1 row affected (0.00 sec) mysql> insert into DemoTable1948 values('Sam_346'); Query OK, 1 row affected (0.00 sec)Display all records from the table using select statement −mysql> ...
Read MoreMySQL SELECT from a subquery and then perform DELETE?
Let us first create a table −mysql> create table DemoTable1947 ( Id int, Name varchar(20) ); Query OK, 0 rows affected (0.00 sec)Insert some records in the table using insert command −mysql> insert into DemoTable1947 values(101, 'Chris'); Query OK, 1 row affected (0.00 sec) mysql> insert into DemoTable1947 values(102, 'David'); Query OK, 1 row affected (0.00 sec) mysql> insert into DemoTable1947 values(103, 'Mike'); Query OK, 1 row affected (0.00 sec) mysql> insert into DemoTable1947 values(104, 'Bob'); Query OK, 1 row affected (0.00 sec) mysql> insert into DemoTable1947 values(105, 'Sam'); Query OK, 1 row affected (0.00 sec)Display ...
Read MoreFetch the count of a specific date in a MySQL table
Let us first create a table −mysql> create table DemoTable1946 ( ShippingDate date ); Query OK, 0 rows affected (0.00 sec)Insert some records in the table using insert command −mysql> insert into DemoTable1946 values('2019-12-11'); Query OK, 1 row affected (0.00 sec) mysql> insert into DemoTable1946 values('2018-12-11'); Query OK, 1 row affected (0.00 sec) mysql> insert into DemoTable1946 values('2017-12-11'); Query OK, 1 row affected (0.00 sec) mysql> insert into DemoTable1946 values('2019-04-22'); Query OK, 1 row affected (0.00 sec) mysql> insert into DemoTable1946 values('2019-12-11'); Query OK, 1 row affected (0.00 sec) mysql> insert into DemoTable1946 values('2015-12-11'); Query OK, 1 ...
Read MoreInsert records from multiple tables in MySQL
To insert records from multiple tables, use INSERT INTO SELECT statement. Here, we will insert records from 2 tables.Let us first create a table −mysql> create table DemoTable1943 ( Name varchar(20) ); Query OK, 0 rows affected (0.00 sec)Insert some records in the table using insert command −mysql> insert into DemoTable1943 values('Chris'); Query OK, 1 row affected (0.00 sec) mysql> insert into DemoTable1943 values('Robert'); Query OK, 1 row affected (0.00 sec)Display all records from the table using select statement −mysql> select * from DemoTable1943;This will produce the following output −+--------+ | Name | +--------+ | Chris ...
Read MoreHow to fetch all databases with name having upper case character after some word using MySQL?
For this, use regular expression. The syntax is as follows −select * from information_schema.schemata WHERE SCHEMA_NAME REGEXP '^yourValue_+[A-Z]';Let us create some databases −mysql> create database bank_APP1; Query OK, 1 row affected (0.00 sec) mysql> create database bank_APP2; Query OK, 1 row affected (0.00 sec) mysql> create database bank_APP3; Query OK, 1 row affected (0.00 sec)Here is the query to get all databases having upper case character after some word −mysql> select * from information_schema.schemata WHERE SCHEMA_NAME REGEXP '^bank_+[A-Z]';This will produce the following output −+--------------+-------------+----------------------------+------------------------+----------+ | CATALOG_NAME | SCHEMA_NAME | DEFAULT_CHARACTER_SET_NAME | DEFAULT_COLLATION_NAME | SQL_PATH | +--------------+-------------+----------------------------+------------------------+----------+ | def ...
Read MoreReturn the field with highest count in MySQL
To return the field with highest count, use ORDER BY COUNT(*). Let us first create a table −mysql> create table DemoTable1940 ( FirstName varchar(20) ); Query OK, 0 rows affected (0.00 sec)Insert some records in the table using insert command −mysql> insert into DemoTable1940 values('Chris'); Query OK, 1 row affected (0.00 sec) mysql> insert into DemoTable1940 values('Mike'); Query OK, 1 row affected (0.00 sec) mysql> insert into DemoTable1940 values('Adam'); Query OK, 1 row affected (0.00 sec) mysql> insert into DemoTable1940 values('Mike'); Query OK, 1 row affected (0.00 sec) mysql> insert into DemoTable1940 values('Chris'); Query OK, 1 row ...
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