When moving a WordPress Multisite blog to a standalone WordPress install that will then be converted to Multisite with new subsites... we can't have users having capabilities and other usermeta that are iodentified for a particular blog id that will change in the future. So this monstrosity selects everything except options that are prefixed wp_…

gistfile1.sql

CREATE OR REPLACE
  VIEW v AS 
	SELECT DISTINCT(meta_key) 
	FROM wp_usermeta 
	WHERE NOT( meta_key REGEXP '^wp_5_{1}')
		AND (meta_key REGEXP '^wp_(.)+');
DELETE FROM wp_usermeta 
WHERE meta_key IN
	(SELECT * FROM v);
UPDATE wp_usermeta 
SET meta_key = REPLACE(
	meta_key,
	'wp_5_',
	'wp_'
);
DROP VIEW v;
DROP TABLE IF EXISTS
	wp_commentmeta, 
	wp_comments, 
	wp_links, 
	wp_options, 
	wp_popularpostsdata, 
	wp_popularpostscache, 
	wp_postmeta, 
	wp_posts, 
	wp_term_relationships, 
	wp_term_taxonomy, 
	wp_terms;
RENAME TABLE
	wp_5_commentmeta TO wp_commentmeta,
	wp_5_links TO wp_links,
	wp_5_comments TO wp_comments,
	wp_5_options TO wp_options,
	wp_5_popularpostsdata TO wp_popularpostsdata,
	wp_5_popularpostsdatacache TO wp_popularpostsdatacache,
	wp_5_postmeta TO wp_postmeta,
	wp_5_posts TO wp_posts,
	wp_5_term_relationships to wp_term_relationships,
	wp_5_term_taxonomy TO wp_term_taxonomy,
	wp_5_terms TO wp_terms;
UPDATE wp_options SET
	option_name = REPLACE(
		option_name,
		'wp_5_',
		'wp_'
	)