In Mysql, EXISTS and IF EXISTS are the two different provisions. EXISTS clause is used to test the presence of the records in the subqueries. If the subquery contains at least one record the EXISTS clause returns true else returns false. The main query utilizes this as the deciding factor ...
MySQL5.6has already supportedmemcached, so we can say MySQL is a mixture of RDBMS and NoSQL. But there is few materials about how to install memcached in MySQL and how to use it, and that is the reason i write this article. In this article, i will show you how to install memcached ...
In our daily development process, sometimes the index is invalid due to the function call to the index column. For example, if we want to query records by month, and when we only store time in the table, if we use the following statement, where create_time is the index column select c...
Now let’s see how to force execution of the query on the Primary node. The MySQL Router offers the possibility of using a query attribute to force the Read/Write Split decision:router.access_mode. Add the following line just before executing the query (cursor.execute(query)): cursor.add_...
Implement SELECT With INSTR() for String Occurrence QueryBuilding upon the previous example with the products table and the objective of checking if the string widget occurs in any product names, we’ll now use the INSTR() function.-- Check if "widget" occurs in any product name SELECT * ...
Mainly throughout the course, we will use this operator with the SELECT command, which comes under Data Query Language (DQL). The SELECT command selects the table from which we need to fetch the records, WHERE clause is used as passing conditions in a query. ...
Step 7: Check Query Time Finally, check all the above-executed queries time, use the “SHOW” command with the “PROFILES” option: SHOW PROFILES; In the above-stated command, the “PROFILES” option is used to show detailed information about each statement: ...
are great objects in MySQL. They allow to keep some “state” for the life of a session: a session can execute a statement to compute a value, store that value in a user variable, and use it in all next statements. This avoids recalculating the same value in each of the next stat...
How to use If condition in Joins How to use if else condition in case statement using sql server 2008? how to use IF statement in subquery how to use IF-THEN-ELSE in a inline table-valued function how to use iif in sql server 2008? How to use like operator in dynamic query? How ...
We can use the AND clause to combine two columns in our query if we want a more specific result. For instance, let’s say we want to filter where the age is greater than 27 and where the course is not equal to “IT”. Our command is as follows: ...