![]() ![]() Within the code first we will connect to MySQL database. We can execute the above code and display records by using PHP. Storing sum of each record in different table PHP code to display Please show an example of the desired output if you want us to give a meaningful answer. This will be useful for final report printing or displaying. 1 The two queries aren't compatible, as they're currently written: One returns a single record with a single column, the other will return many columns in X rows. We can store sum of marks in each subjects of each student in a different table. WHEN sum(social + math + science ) >=170 THEN 'C' WHEN sum(social + math + science ) >=200 THEN 'B' Read more on CASE WHEN THEN statement here.ĬASE WHEN sum(social + math + science ) >= 225 THEN 'A' Here we will check total mark against set marks for different levels of grade and allot Grade accordingly. MySQL Case query executes the statement based on the matching condition. We can display grade of the student by using CASE statement in our Query. Show Grade based on the total mark ( using CASE statement ) Sum(social)+sum(math)+sum(science) from student_sum Note that we have to maintain same number of columns while using UNION query. Like we do in MS Excel we can display sum of all columns and the sum of all total subject marks by using UNION. LEAST(social,science,math) as min FROM student_sum idĭisplaying sum of all columns at last row We can list starting from highest mark to lowest mark by using Order By Query.įrom student_sum GROUP BY id ORDER BY Total DESC Displaying highest & lowest mark in all subjects of each student SELECT id,name,GREATEST(social,science,math) as max, Listing all columns along with aggregate functions like sum(), max() using over() with partition → Displaying from Highest to lowest SELECT id,name,class, social, math, science, Note that id is unique value column in our table. Now we will try to display all marks and sum of them for each student by using group by. Query to display percentage value using 2 decimal places.įORMAT((( social + science + math)/(95*3) * 100),2) AS percentageįROM `student_sum` Sum of the row data of each record The above percentage data is having four decimal places, we can format these numbers by using ROUND Sql command. (( social + science + math)/(95*3) * 100) AS percentage SELECT id, name, class,( social + science + math) as Total, SELECT name, (( social + science + math)/(95*3) * 100) AS percentageįROM `student_sum` Displaying Total Mark with Percentageīoth total mark and percentage we can display like this ![]() ![]() So to get the percentage mark of each student we have to multiply 95 with 3 ( for three subjects ) and then divide that from the total and multiply with 100 here is the query. Let us assume the full mark in each subject is 95. We can add various other sql commands like where clause etc. SELECT sum(social + math + science ) as total So the sum is to be collected in all three columns. Now we will try to get sum of marks of all students in all subjects. So again, the above statement will count only the rows where neither col1 nor col2 is null.Related Tutorial MySQL SUM MySQL Max MySQL Min MySQL AvgĪs you can see the above sum is sum of marks of each student. Adding up ( SUM) the 1s is equivalent to counting the truths. With only 1s and 0s the * operator works as an equivalent of the logical AND: the final result will be 1 (True) only if each operand is 1 otherwise the result will be 0 (False). In the context of the arithmetic operator * the logical result of the IS NOT NULL operator is implicitly converted to a number, 1 for True, 0 for False. SUM( (col1 IS NOT NULL) * (col2 IS NOT NULL) ) In particular, you could replace the COUNT with SUM and treat the predicates as numbers (1/0) in an arithmetic expression: SELECT It is possible to shorten the expression somewhat by choosing a less clear syntax. The obvious flaw of this workaround (either variation) is that it is clearly rather unwieldy and will become ridiculously long very quickly as you add more columns to account for. A row will be counted only if neither col1 nor col2 is null. Where instead of the 1 you can put any non-null constant. Or the MySQL-specific IF function: SELECTĬOUNT(IF(col1 IS NOT NULL AND col2 IS NOT NULL, 1, NULL)) It could be either the standard-compliant CASE: SELECTĬOUNT(CASE WHEN col1 IS NOT NULL AND col2 IS NOT NULL THEN 1 END) ![]() If that last aspect of the behaviour is what you are trying to achieve, you could emulate it using a conditional inside COUNT. However, one other important point is that a tuple is counted only if none of the individual values in the tuple is null. Obviously, COUNT(DISTINCT) with multiple columns counts unique combinations of the specified columns' values. ![]()
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