sql 实现 动态条件查询

SELECT
   *
FROM
    ZHC_VSL_DEV_ENCODER_CHN chn LEFT JOIN
    ZHC_VSL_DEV_ENCODER_DEV dev ON  chn.DEVICECODE = dev.DEVICEID
WHERE
    1 = 1 
    AND (
    (${device_type}='1' and dev.category='1') or 
    (${device_type}='2' and dev.category='5' AND ( instr(','||chn.cameraFunctions||',',',8,')>0 or instr(','||chn.cameraFunctions||',',',12,')>0 or instr(','||chn.cameraFunctions||',',',10,')>0)) or 
    (${device_type}='3' and chn.device_type='3') or
    (${device_type}='4' and dev.category='5' AND (instr(','||chn.cameraFunctions||',',',9,')>0 or instr(','||chn.cameraFunctions||',',',10,')>0))
    )

${device_type} 为条件值，不同的${device_type}，查询条件不同。