LoopBack API中where多条件过滤时AND运算符是否冗余？

Great question! Let me break this down clearly based on LoopBack's query behavior:

Yes, explicitly using the and operator in a multi-condition where filter is redundant—LoopBack defaults to treating multiple top-level conditions as an AND relationship automatically.

Why your tests returned identical results #

When you write a where filter like this (without and):

YourModel.find({
  where: {
    columnA: 'value1',
    columnB: 123
  }
})

LoopBack internally interprets this exactly the same as if you wrote it with the explicit and operator:

YourModel.find({
  where: {
    and: [
      { columnA: 'value1' },
      { columnB: 123 }
    ]
  }
})

Both queries fetch records that match all specified conditions, which is why you got the same first record in your tests.

When you actually need to use and #

The only time you need to explicitly use and is when combining nested logical conditions (like mixing AND with OR). For example:

YourModel.find({
  where: {
    and: [
      { columnA: 'value1' },
      {
        or: [
          { columnB: 123 },
          { columnC: 'value3' }
        ]
      }
    ]
  }
})

Here, the explicit and is necessary to group the top-level condition with the nested or block.

A quick note on readability #

While writing and explicitly isn't an error, it adds unnecessary verbosity. The default syntax (listing conditions side-by-side) is the standard, concise way to express AND logic in LoopBack queries. That said, if your team prefers the explicit version for clarity, there's no harm in using it—just know it's not required.

内容的提问来源于stack exchange，提问作者KRO