Function execute_call 

pub fn execute_call(
    stmt: &CallStmt,
    db: &mut Database,
) -> Result<(), ExecutorError>

Execute CALL statement (SQL:1999 Feature P001)

Executes a stored procedure with parameter binding and procedural statement execution.

Parameter Binding

• IN parameters: Values are evaluated and passed to the procedure
• OUT parameters: Must be session variables (@var), initialized to NULL, procedure can assign values that are returned to caller
• INOUT parameters: Must be session variables (@var), values are passed in and can be modified by the procedure

Example

-- Create procedure with mixed parameter modes
CREATE PROCEDURE update_counter(
  IN increment INT,
  INOUT counter INT,
  OUT message VARCHAR(100)
)
BEGIN
  SET counter = counter + increment;
  SET message = CONCAT('Counter updated to ', counter);
END;

-- Call procedure
SET @count = 10;
CALL update_counter(5, @count, @msg);
SELECT @count, @msg;
-- Output: count=15, msg='Counter updated to 15'

Control Flow

The procedure body executes sequentially until:

• All statements complete (normal exit)
• RETURN statement is encountered (early exit)
• Error occurs (execution stops)

After execution, OUT and INOUT parameter values are written back to their corresponding session variables.

Errors

Returns error if:

• Procedure not found
• Wrong number of arguments
• OUT/INOUT parameter is not a session variable
• Type mismatch in parameter binding
• Execution error in procedure body