How to execute a stored procedure inside a select query

Using cursors and temporary tables — when and how?

Amidst the maze of SQL, you might occasionally find a tricky beast called a stored procedure that doesn't easily morph into a function. Fear not brave adventurer, therein come cursors and temporary tables to your aid!

Row-per-row combat using cursors

To meet the adversary one row at a time, enlist your trusty cursor within the fortress of your stored procedure for iteration triumph:

DECLARE CursorName CURSOR FOR
SELECT Column1 FROM YourTable;

OPEN CursorName 
FETCH NEXT FROM CursorName INTO @Var; -- Unleash the chronomancer (time traveler)

WHILE @@FETCH_STATUS = 0
BEGIN
   -- A foe for each time fragment! Call thine mighty spell
   EXEC YourStoredProcedure @Var; 
   FETCH NEXT FROM CursorName INTO @Var;
END

CLOSE CursorName; -- Timeshift ritual ends
DEALLOCATE CursorName; -- Return the chronomancer to its slumber


Beware lone ranger! Jewel as it is, this method illuminates the dark side of performance due to row-by-row brawling. Use judiciously!

Result hoarding with temporary tables

To gather spoils from your victorious battles with stored procedures, construct a temporary storage vault:

CREATE TABLE #TempTable (Column1 DataType, Column2 DataType, ...); -- Build ye fort!

INSERT INTO #TempTable
EXEC YourStoredProcedure; -- Gather your rewards!

-- Now you can treat your eyes on the spoils
SELECT * FROM #TempTable
JOIN AnotherTable ON #TempTable.Column1 = AnotherTable.Column1; 

-- Grand feast ends, time to rest
DROP TABLE #TempTable; -- Dismiss the ghost builders!


Aye, this proves handy when ye stored procedure uncovers a treasure trove of records that beg to be put to further tests and trials.

Transmogrifying stored procedures to functions

In the realm where time is a luxury and you can weave your stored procedure's logic into set-based operations, consider transforming it into a function. Here are some scrolls of wisdom for this endeavour:

Using the right tool (or spell!) for the task

While scalar-valued functions can join the ranks within a SELECT query, avoid sending them to heavy-duty data manipulation battles with their limited weaponry. Here, your stalwart stored procedures come charging with their flexibility and temporary storage shields.

Scroll of Comparison

Balance with care, the potential of SQL Server's functions and stored procedures for the mission. Functions often serve well for intellectual exercises, while stored procedures brace for the onslaught of heavy-duty operations and high transactional wars.

The art of performance wrestling

Cursors and temp tables, though helpers, could turn fiendish on your kingdom's performance! Gauge the importance of these against their impact. Remember, valiant knights practice pre-calculation and favour battle formations over individual duels!

Common scenarios and alternatives

Apart from the trusty methods gathered so far, the ancients inscribed techniques to help you streamline the process of invoking a stored procedure within a SELECT command, while keeping a firm grip on performance.

Pre-calculation Valor

If time permits, show pre-calculation prowess and store results in permanent tables for easy access and more efficient questing.

Duel of Real-time vs Batch processing

Consider the urgency of real-time execution vs the finesse of batch processing. Real-time may demand cunning tricks (cursors, temp tables), while batch allows you to restructure logic into a scheduled choreography.

The .NET Dagger: SQL CLR

For challenges that defy the serenity of T-SQL, invoke the power of SQL CLR (Common Language Runtime Integration). This will enable you to craft .NET functions or stored procedures and tackle the most complex of operations.