SELECT column for a row only if its value is not empty

sqlite

I want to display a certain column only if its value is not empty.

Pseudo code:

SELECT column1, IF_NOT_EMPTY(column2), ... FROM table;

Will display all columns except column2 if column2 is empty.

Best Answer

Not sure there is a way to do that with standard sql you could use case to change that blank to a value https://www.geeksforgeeks.org/sql-case-statement/

The consensus here was that this shouldn't be done on the DB side rather, in whatever mechanism is presenting the data: Hide column if any value is null or zero via proc sql or view

Related Solutions

Select column from ALL tables

You're looking for UNION and UNION ALL.

select my_column from table1
union all
select my_column from table2
union all
select my_column from ...

But needing to select one column from every table is likely the sign of a significant design error.

SQLite – How to Select All Rows with a Minimum Value

As you have seen, a simple GROUP BY will not work because it would return only one record per group.

Your join works fine. For a large table, it will be efficient only if there is an index on the join columns (num and text).

Alternatively, you could use a correlated subquery:

SELECT *
FROM t
WHERE num = (SELECT MIN(num)
             FROM t AS t2
             WHERE t2.text = t.text);

SQLFiddle

When being executed, this query does not require a temporary table (your query does for the result of u), but will execute the subquery for each record in t, so text should be indexed. (Or use an index on both text and num to get a covering index.)

Best Answer

Related Solutions

Select column from ALL tables

SQLite – How to Select All Rows with a Minimum Value

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