code: func (v *typeInferrer) handleLikeExpr(x *ast.PatternLikeExpr) {
  	x.SetType(types.NewFieldType(mysql.TypeLonglong))
  	x.Type.Charset = charset.CharsetBin
  	x.Type.Collate = charset.CollationBin
  	x.Expr = v.addCastToString(x.Expr)
  	x.Pattern = v.addCastToString(x.Pattern)
  }
docs: // like expression expects the target expression and pattern to be a string, if it's not, we add a cast function.