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DROP TABLE IF EXISTS yourTable; CREATE TABLE yourTable (crm_id varchar(55), customer_id int); INSERT INTO yourTable (crm_id, customer_id) VALUES ('jon', 12345), ('jon', 12346), ('ben', 12347), ('sam', 12348); SELECT cnt AS crm_id_cnt, COUNT(*) AS num_customer_ids FROM ( SELECT crm_id, COUNT(DISTINCT customer_id) AS cnt FROM yourTable GROUP BY crm_id ) t GROUP BY cnt;
Records: 4 Duplicates: 0 Warnings: 0
crm_id_cnt
num_customer_ids
1
2
2
1