db.dbtestregex.find({data:{ $regex:'<Head>OK<\/Head>'}})
db.dbtestregex.find({data:{ $not: /<Head>OK<\/Head>/ }})
{
"_id" : ObjectId("5d305b1c4857fc49c0c14c81"),
"order" : "QQ00001",
"data" : "\"<?xml version='1.0' encoding='UTF-8'?><Response service=\\\"OrderService\\\"><Head>ERR</Head><ERROR>重复下单</ERROR></Response>\""
},
{
"_id" : ObjectId("5d305b3b4857fc49c0c14c82"),
"order" : "QQ00001",
"data" : "\"<?xml version='1.0' encoding='UTF-8'?><Response service=\\\"OrderService\\\"><Head>ERR</Head><ERROR>重复下单</ERROR></Response>\""
},
{
"_id" : ObjectId("5d305b404857fc49c0c14c83"),
"order" : "QQ00002",
"data" : "\"<?xml version='1.0' encoding='UTF-8'?><Response service=\\\"OrderService\\\"><Head>ERR</Head><ERROR>重复下单</ERROR></Response>\""
},
{
"_id" : ObjectId("5d305b454857fc49c0c14c84"),
"order" : "QQ00002",
"data" : "\"<?xml version='1.0' encoding='UTF-8'?><Response service=\\\"OrderService\\\"><Head>ERR</Head><ERROR>重复下单</ERROR></Response>\""
},
{
"_id" : ObjectId("5d305b4b4857fc49c0c14c85"),
"order" : "QQ00003",
"data" : "\"<?xml version='1.0' encoding='UTF-8'?><Response service=\\\"OrderService\\\"><Head>ERR</Head><ERROR>重复下单</ERROR></Response>\""
},
{
"_id" : ObjectId("5d305b4f4857fc49c0c14c86"),
"order" : "QQ00003",
"data" : "\"<?xml version='1.0' encoding='UTF-8'?><Response service=\\\"OrderService\\\"><Head>ERR</Head><ERROR>重复下单</ERROR></Response>\&qu