R中sqldf中SQL语句的问题？

如何解决R中sqldf中SQL语句的问题？

我遇到了一些关于 sqldf 的非常紧张的问题。

示例：

sqldf("select REGN,NII from dataframe ")

即使使用非常简单的查询，此函数也会返回以下错误：

Ошибка в result_create(conn@ptr,statement) :too many sql variables

这是我使用的数据样本作为 dput(head(dataframe))

structure(list(REGN = c(1L,21L,23L,52L,53L,55L),NII = c(5136380L,30322L,291812L,92561L,120618L,140652L)),row.names = c(NA,6L),class = "data.frame")

编辑： 但是当我对这个数据帧运行类似的代码时：

structure(list(date_start = c("2008-04-01","2016-04-01","2019-04-01","2020-04-01","2021-04-01"),date_end = c("2016-04-01","2021-04-01","3000-01-01")),-5L),class = c("tbl_df","tbl","data.frame"))

一切正常。

sessioninfo() 的结果：

R version 3.5.3 (2019-03-11)
Platform: x86_64-w64-mingw32/x64 (64-bit)
Running under: Windows 10 x64 (build 19041)

Matrix products: default

locale:
[1] LC_COLLATE=Russian_Russia.1251 
[2] LC_CTYPE=Russian_Russia.1251   
[3] LC_MONETARY=Russian_Russia.1251
[4] LC_NUMERIC=C                   
[5] LC_TIME=Russian_Russia.1251    

attached base packages:
[1] stats     graphics  Grdevices utils     datasets  methods  
[7] base     

other attached packages:
 [1] openxlsx_4.1.0       sqldf_0.4-11        
 [3] Rsqlite_2.1.1        gsubfn_0.7          
 [5] proto_1.0.0          stringr_1.4.0       
 [7] reshape2_1.4.3       dplyr_0.8.0.1       
 [9] readxl_1.3.1         foreign_0.8-71      
[11] RevoUtils_11.0.3     RevoUtilsMath_11.0.0

loaded via a namespace (and not attached):
 [1] zip_2.0.1        Rcpp_1.0.1       cellranger_1.1.0
 [4] pillar_1.3.1     compiler_3.5.3   plyr_1.8.4      
 [7] tools_3.5.3      RPostgres_1.1.1  digest_0.6.18   
[10] bit_1.1-14       memoise_1.1.0    tibble_2.1.1    
[13] pkgconfig_2.0.2  rlang_0.3.4      DBI_1.0.0       
[16] rstudioapi_0.10  hms_0.4.2        bit64_0.9-7     
[19] tidyselect_0.2.5 glue_1.3.1       R6_2.3.0        
[22] tcltk_3.5.3      purrr_0.3.2      blob_1.1.1      
[25] magrittr_1.5     assertthat_0.2.1 stringi_1.4.3   
[28] chron_2.3-53     Crayon_1.3.4 

ls() 的结果：

[1] "complete"             "con"                 
 [3] "dateAn"               "df"                  
 [5] "df_3"                 "df_4"                
 [7] "df_inval"             "df_inval_q"          
 [9] "df_itogo"             "df_itogo_q"          
[11] "df_itogo2"            "df_rub"              
[13] "df_rub_q"             "df1"                 
[15] "f102_dates"           "f102_maket"          
[17] "f102_maket_1"         "f102_maket_long"     
[19] "f102_maket_long_symb" "i"                   
[21] "j"                    "k"                   
[23] "levelFunc"            "listdbf"             
[25] "m"                    "MainPath"            
[27] "query_compos"         "split"               
[29] "subtract"         

怎么了？