how-to-add-where-clause-to-wp-query-1.php

<?php

// Hook the filter before calling the query. Note that we are using an anonymous 
// function here and saving a reference to the `$fn` variable for use further down.
add_filter( 'posts_where', $fn = function ( $where, WP_Query $wp_query ){
	global $wpdb;
	
	// Add a clause that ensures we only get posts with an ID greater than 200.
 	$where .= " AND {$wpdb->posts}.ID > 200";
	
	return $where;
}, 10, 2 );

// Make the query.
$query = new WP_Query( [
	'post_type' => 'post',
	'posts_per_page' => 10,
] );

// Remove the filter after calling the query so it doesn't affect any subsequent queries.
remove_filter( 'posts_where', $fn, 10 );

how-to-add-where-clause-to-wp-query-2.php

<?php

// Hook the filter before calling the query. Note that we are using an anonymous 
// function here and saving a reference to the `$fn` variable for use further down.
add_filter( 'posts_clauses', $fn = function ( $pieces, WP_Query $wp_query ){
	global $wpdb;
	
	// Add a clause that ensures we only get posts with an ID greater than 200.
 	$pieces['where'] .= " AND {$wpdb->posts}.ID > 200";
	
	return $pieces;
}, 10, 2 );

// Make the query.
$query = new WP_Query( [
	'post_type' => 'post',
	'posts_per_page' => 10,
] );

// Remove the filter after calling the query so it doesn't affect any subsequent queries.
remove_filter( 'posts_clauses', $fn, 10 );

how-to-add-where-clause-to-wp-user-query.php

<?php

add_action( 'pre_user_query', $fn = function ( WP_User_Query $query ) {
	global $wpdb;
	$query->query_where .= " AND {$wpdb->users}.ID > 1";
} );

$query = new WP_User_Query( [
	'orderby' => 'ID',
	'order' => 'ASC',
	'fields' => 'ID',
	'count_total' => false,
] );

remove_action( 'pre_user_query', $fn );