在相同的結果集內對新創建的變量進行SQL計數

Question

所以我正在從現有表中讀取一些信息並創建一個新變量（wgtdiff），它是原始數據表中兩個變量的差異，然後將它們放入因爲我想知道有多少人口有0-5,5-10等的差別......我想要的是能夠顯示出多少百分比的人口屬於哪個桶（比如說0-5被認爲是一個桶）。我找到了原始表格的例子，並嘗試過並且沒有奏效。我可以計算一個我剛創建的變量嗎？下面是我有：

select heat_no as HeatNo, grade_id as Grade, strand_no as Strand, 
     cast_seq as CastSeq, billet_weight as bli_billet_weight, 
     plc_weight as bli_plc_weight, billet_date as bli_billet_date, 
     round ((bli_plc_weight - bli_billet_weight),2) as Wgtdiff_plc_aim, 
     CASE WHEN abs(round((bli_plc_weight - bli_billet_weight),2)) <= 5 THEN '0 to +/- 5' 
      WHEN abs(round((bli_plc_weight - bli_billet_weight),2)) between 5.01 and 10 THEN '+/- 5 to 10' 
      WHEN abs(round((bli_plc_weight - bli_billet_weight),2)) between 10.01 and 15 THEN '+/- 10 to 15' 
      WHEN abs(round((bli_plc_weight - bli_billet_weight),2)) between 15.01 and 20 THEN '+/- 15 to 20' 
      Else 'Greater than +/- 20' 
     END as CASE 
from Billet_table 

Answer 1

只需使用一個子查詢：

select HeatNo, Grade, Strand, CastSeq, bli_billet_weight, bli_plc_weight, bli_billet_date,Wgtdiff_plc_aim 
CASE WHEN abs(round((bli_plc_weight - bli_billet_weight),2)) <= 5 THEN '0 to +/- 5' 
    WHEN abs(round((bli_plc_weight - bli_billet_weight),2)) <= 10 THEN '+/- 5 to 10' 
    WHEN abs(round((bli_plc_weight - bli_billet_weight),2)) <= 15 THEN '+/- 10 to 15' 
    WHEN abs(round((bli_plc_weight - bli_billet_weight),2)) <= 20 THEN '+/- 15 to 20' 
    Else 'Greater than +/- 20' 
END as CASE 
from (select heat_no as HeatNo, grade_id as Grade, strand_no as Strand, 
      cast_seq as CastSeq, billet_weight as bli_billet_weight, 
      plc_weight as bli_plc_weight, billet_date as bli_billet_date, 
      round ((plc_weight - billet_weight),2) as Wgtdiff_plc_aim 
    from Billet_table) temp