You tried to set this variable to t, it looks like the behavior you want.
SQL-pop-to-buffer-after-send-region
After calling sql-send-region' or sql-send-buffer', the window is broken and the SQLi buffer is displayed. If this variable is not equal to zero, this buffer window will be selected by calling pop-to-buffer'. If this variable is nil, that buffer is shown using pop-to-buffer'. If this variable is nil, that buffer is shown using display-buffer '.
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