diff --git a/pg4wp/driver_pgsql.php b/pg4wp/driver_pgsql.php
index 8807668..375fd3a 100644
--- a/pg4wp/driver_pgsql.php
+++ b/pg4wp/driver_pgsql.php
@@ -281,6 +281,22 @@
 			$pattern = '/DATE_ADD[ ]*\(([^,]+),([^\)]+)\)/';
 			$sql = preg_replace( $pattern, '($1 + $2)', $sql);
 
+			// Convert MySQL FIELD function to CASE statement
+			// https://dev.mysql.com/doc/refman/5.7/en/string-functions.html#function_field
+			// Other implementations:  https://stackoverflow.com/q/1309624
+			function pg4wp_rewrite_field($matches)
+			{
+				$case = 'CASE ' . trim($matches[1]);
+				$comparands = explode(',', $matches[2]);
+				foreach($comparands as $i => $comparand) {
+					$case .= ' WHEN ' . trim($comparand) . ' THEN ' . ($i + 1);
+				}
+				$case .= ' ELSE 0 END';
+				return $case;
+			}
+			$pattern = '/FIELD[ ]*\(([^\),]+),([^\)]+)\)/';
+			$sql = preg_replace_callback( $pattern, 'pg4wp_rewrite_field', $sql);
+
 			$pattern = '/GROUP_CONCAT\(([^()]*(\(((?>[^()]+)|(?-2))*\))?[^()]*)\)/x';
 			$sql = preg_replace( $pattern, "string_agg($1, ',')", $sql);