How to turn a row into a column in MySQL?
Basically I want to turn each row in table B into a column in the result table. If there was a new entry was added to table B for id=1, then I want the result table to automatically extend by one column to accommodate this extra data point. You can use GROUP BY and MAX to simulate pivot. MySQL also supports IF statement.
How can I add more columns to the base table?
Step 1: select columns of interest. In the desired result, hostid provides the y-values and itemname provides the x-values. Step 2: extend the base table with extra columns. We typically need one column per x-value.
How do I UNPIVOT a table in MySQL?
What you need to do is first, unpivot the data and then pivot it. But unfortunately MySQL does not have these functions so you will need to replicate them using a UNION ALLquery for the unpivot and an aggregate function with a CASEfor the pivot.
Is there way to simulate pivot in MySQL?
You can use GROUP BY and MAX to simulate pivot. MySQL also supports IF statement. And here is the SQL Fiddle. Thanks for contributing an answer to Stack Overflow!
How to convert rows to columns in SQL Server?
In SQL Server you can use the PIVOT function to transform the data from rows to columns: select Firstname, Amount, PostalCode, LastName, AccountNumber from ( select value, columnname from yourtable ) d pivot ( max(value) for columnname in (Firstname, Amount, PostalCode, LastName, AccountNumber) ) piv; See Demo.
How to list 1 to n rows in MySQL?
This will list 1 to n row items separated by commas. Group_Concat makes this possible in MySQL.
Are there any limitations to transposing rows into columns?
The major limitation of transposing rows into columns using T-SQL Cursor is a limitation that is linked to cursors in general – they rely on temporary objects, consume memory resources and processes row one at a time which could all result into significant performance costs.
Is the number of columns in a query fixed?
The number of columns of query is fixed but the values are dynamic and based on values of rows. You can build it So, I use one query to build the table header and another one to see the values:
How to change number of rows to columns in SQL?
Note that we didn’t change the number of rows — we just added extra columns. Also note the pattern of NULL s — a row with itemname = “A” has a non-null value for new column A, and null values for the other new columns.