通常我对SQL查询非常有信心,但是这个让我摸不着头脑.我觉得这应该是一个快速修复,但我只是没有看到它.
我试图在一个查询中对同一个表上的多个值进行计数.
不要介意“0000000000000000”,它只是表示一个空字节数组.
@H_502_12@SELECT COUNT(ssn) FROM patients WHERE ssn="0000000000000000"; SELECT COUNT(firstname) FROM patients WHERE firstname="0000000000000000" SELECT COUNT(lastname) FROM patients WHERE lastname="0000000000000000" etc...
最佳答案
你可以这样做 –
@H_502_12@SELECT COUNT(ssn) AS patient_count,'ssn' AS count_type FROM patients WHERE ssn="0000000000000000"; UNION SELECT COUNT(firstname) AS patient_count,'firstname' AS count_type FROM patients WHERE firstname="0000000000000000" UNION SELECT COUNT(lastname) AS patient_count,'lastname' AS count_type FROM patients WHERE lastname="0000000000000000"