Sharon Christine has Published 436 Articles

MySQL query with two boolean conditions to extract date based on hour?

Sharon Christine

Sharon Christine

Updated on 30-Jun-2020 13:24:50

87 Views

Let us first create a table −mysql> create table DemoTable    -> (    -> AdmissionDate datetime    -> ); Query OK, 0 rows affected (0.75 sec)Insert some records in the table using insert command −mysql> insert into DemoTable values('2019-01-10 10:45:10'); Query OK, 1 row affected (0.30 sec) mysql> ... Read More

Remove all except the first character of a string in MySQL?

Sharon Christine

Sharon Christine

Updated on 30-Jun-2020 13:24:00

171 Views

For this, use the LEFT() method, which returns a specified number of characters from the left of the string.Let us first create a table −mysql> create table DemoTable    -> (    -> FirstName varchar(100)    -> ); Query OK, 0 rows affected (0.96 sec)Insert some records in the table ... Read More

How do I select 5 random rows from the 20 most recent rows in MySQL?

Sharon Christine

Sharon Christine

Updated on 30-Jun-2020 13:22:49

375 Views

For random, use RAND() method. And for limit on rows, use the LIMIT() method.Let us first create a table −mysql> create table DemoTable    -> (    -> ShippingDate datetime    -> ); Query OK, 0 rows affected (0.51 sec)Insert some records in the table using insert command −mysql> insert ... Read More

How to get everything before the last occurrence of a character in MySQL?

Sharon Christine

Sharon Christine

Updated on 30-Jun-2020 12:55:53

437 Views

You can use below syntax. Following is the syntax −update yourTableName set yourColumnName=REVERSE(SUBSTRING(REVERSE(yourColumnName), INSTR(REVERSE(yourColumnName), '.')));Let us first create a table −mysql> create table DemoTable -> ( -> Words text -> ); Query OK, 0 rows affected (0.51 sec)Insert some records in the table using insert command −mysql> insert into DemoTable ... Read More

How to update data in a MySQL database without removing the old data?

Sharon Christine

Sharon Christine

Updated on 30-Jun-2020 12:39:56

913 Views

For this, you can use UPDATE and concatenate the new data with the old one to save the old data as well −update yourTableName set yourColumnName=concat(yourColumnName, ", yourValue");Let us first create a table −mysql> create table DemoTable -> ( -> CustomerName varchar(100) -> ); Query OK, 0 rows affected (0.54 ... Read More

MySQL query to return the entire date and time based on a string and format

Sharon Christine

Sharon Christine

Updated on 30-Jun-2020 12:36:03

50 Views

Let us first create a table −mysql> create table DemoTable    -> (    -> AdmissionDate varchar(100)    -> ); Query OK, 0 rows affected (0.66 sec)Insert some records in the table using insert command −mysql> insert into DemoTable values('Wed, 19 Jun 2019 04:10:20'); Query OK, 1 row affected (0.22 ... Read More

Select a fixed number of random records from a MySQL table?

Sharon Christine

Sharon Christine

Updated on 30-Jun-2020 12:35:14

130 Views

For random records, you can use rand() method. To set the number of records, use the LIMIT −select *from yourTableName order by rand() limit numberOfRecords;Let us first create a table −mysql> create table DemoTable    -> (    -> LastName varchar(100)    -> ); Query OK, 0 rows affected (0.51 ... Read More

Store a variable with the result of a MySQL SELECT CASE?

Sharon Christine

Sharon Christine

Updated on 30-Jun-2020 12:34:14

767 Views

For this, use SELECT CASE. Let us first create a table −mysql> create table DemoTable    -> (    -> Num1 int,    -> Num2 int    -> ); Query OK, 0 rows affected (0.65 sec)Insert some records in the table using insert command −mysql> insert into DemoTable values(10, 30); ... Read More

Create a table named “select” in SQL databases?

Sharon Christine

Sharon Christine

Updated on 30-Jun-2020 12:32:59

67 Views

Since “select” is a reserved word in MySQL, we cannot create a table name with it. But, if you still want to create such a table, surround the word select with quote.Let us first create a table −mysql> create table `select` -> ( -> Number int -> ); Query OK, ... Read More

How to order an alphanumeric column in MySQL?

Sharon Christine

Sharon Christine

Updated on 30-Jun-2020 12:16:32

897 Views

To order an alphanumeric column with values like “100X, “2Z”, etc. use the ORDER BY. Let us first create a table −mysql> create table DemoTable -> ( -> StudentId varchar(100) -> ); Query OK, 0 rows affected (0.52 sec)Insert some records in the table using insert command −mysql> insert into ... Read More

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