Build a query that creates NULL indicators for nulls in selected columns.

mark_null_cols(source, cols)

Arguments

source

incoming rel_op tree or data.frame.

cols

named character, values are columns to track, names are where to land indicators.

Value

rel_op node or data.frame (depending on input).

See also

Examples

# WARNING: example tries to change rquery.rquery_db_executor option to RSQLite and back. if (requireNamespace("DBI", quietly = TRUE) && requireNamespace("RSQLite", quietly = TRUE)) { my_db <- DBI::dbConnect(RSQLite::SQLite(), ":memory:") RSQLite::initExtension(my_db) old_o <- options(list("rquery.rquery_db_executor" = list(db = my_db))) d <- rq_copy_to(my_db, 'd', data.frame(AUC = c(0.6, 0.5, NA), R2 = c(1.0, 0.9, NA))) op_tree <- d %.>% mark_null_cols(., qc(AUC_NULL, R2_NULL) %:=% qc(AUC, R2)) cat(format(op_tree)) sql <- to_sql(op_tree, my_db) cat(sql) print(DBI::dbGetQuery(my_db, sql)) # ad-hoc mode data.frame(AUC=c(1,NA,0.5), R2=c(NA,1,0)) %.>% op_tree %.>% print(.) # cleanup options(old_o) DBI::dbDisconnect(my_db) }
#> mk_td("d", c( #> "AUC", #> "R2")) %.>% #> sql_node(., #> mark_null_cols(c('AUC_NULL' = 'AUC', 'R2_NULL' = 'R2'))) #> SELECT #> `AUC` AS `AUC`, #> `R2` AS `R2`, #> `AUC` IS NULL AS `AUC_NULL`, #> `R2` IS NULL AS `R2_NULL` #> FROM ( #> SELECT #> `AUC`, #> `R2` #> FROM #> `d` #> ) tsql_83506579673090640138_0000000000 #> AUC R2 AUC_NULL R2_NULL #> 1 0.6 1.0 0 0 #> 2 0.5 0.9 0 0 #> 3 NA NA 1 1 #> AUC R2 AUC_NULL R2_NULL #> 1 1.0 NA 0 1 #> 2 NA 1 1 0 #> 3 0.5 0 0 0