Campuran kolasi ilegal Kesalahan MySQL

Saya mendapatkan kesalahan aneh ini saat memproses data dalam jumlah besar ... Error Number: 1267 Illegal mix of collations (latin1_swedish_ci,IMPLICIT) and (utf8_general_ci,COERCIBLE) for operation '=' SELECT COUNT(*) as num from keywords WHERE campaignId='12' AND LCASE(keyword)='hello again...