我的宝宝今年一岁半了。为了预防破伤风等疾病，我带着宝宝每个月打一次白破和脊灰疫苗的第一针。因为不知道这两种疫苗能不能一起接种，所以在网上查了两种疫苗的效果。另外，也有一起注射的副作用等。也有人说两种疫
Suppose I have the following query: select * from A, B, C, D where A.x = B.x and B.y = C.y and A.z = D.z I have indexes on A.x and B.x and B.y and C.y and D.z
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