CASE in Select-Anweisung MySQL

Question

Ich habe Fehler in MySQL-Abfrage, so brauche ich eine if-Anweisung basierend auf dem vorherigen Wert auswählen.

hier ist meine Frage,

SELECT 
    ds.master_rcpt_gen, 
    ds.visa_rcpt_gen, 
    dsp.curr_amount, 
    dsp.curr_id, 
    mcr.conv_rate, 
    mcr.curr_code, 
    mcr.curr_desc, 
    mcr.curr_type, 
    (conv_rate/(select mcr.conv_rate from mst_currencies_rate mcr where mcr.curr_code = 'USD')) conv_ratio, 
    curr_amount * (conv_rate/(select mcr.conv_rate from mst_currencies_rate mcr where mcr.curr_code = 'USD')) conv_usd, 
    (select mtr.USD_tax_rate from mst_tax_rate mtr) * (curr_amount * (conv_rate/(select mcr.conv_rate from mst_currencies_rate mcr where mcr.curr_code = 'USD'))) AS conv_taxrate_commission, 
    CASE WHEN mcr.curr_type = 'LOCAL' THEN conv_taxrate_commission = dsp.curr_amount ELSE (select mtr.USD_tax_rate from mst_tax_rate mtr) * (curr_amount * (conv_rate/(select mcr.conv_rate from mst_currencies_rate mcr where mcr.curr_code = 'USD'))) 
    END final_conv_rate 
FROM 
    dtl_sr ds 
INNER JOIN dtl_sr_payment dsp ON dsp.flight_id = ds.flight_id 
AND dsp.sr_id = ds.SR_ID 
INNER JOIN mst_currencies_rate mcr ON mcr.curr_id = dsp.curr_id 

passiert Mein Fehler in case-Anweisung, i die Case-Anweisung brauchen Wert von conv_taxrate_commission zu lesen. IF mcr.curr_type = 'LOCAL' muss conv_taxrate_commission gleich dsp.curr_amount sein, sonst muss ich die conv_taxrate_commission unverändert lassen.

Bitte helfen Sie mir

Answer 1

die Sie interessieren, gehe ich davon aus, wenn mcr.curr_type = 'LOCAL', final_conv_rate ist dsp.curr_amount;)

SELECT 
    ds.master_rcpt_gen, 
    ds.visa_rcpt_gen, 
    dsp.curr_amount, 
    dsp.curr_id, 
    mcr.conv_rate, 
    mcr.curr_code, 
    mcr.curr_desc, 
    mcr.curr_type, 
    (conv_rate/(SELECT mcr.conv_rate 
       FROM mst_currencies_rate mcr 
       WHERE mcr.curr_code = 'USD'))             conv_ratio, 
    curr_amount * (conv_rate/(SELECT mcr.conv_rate 
           FROM mst_currencies_rate mcr 
           WHERE mcr.curr_code = 'USD'))         conv_usd, 
    CASE WHEN mcr.curr_type = 'LOCAL' 
    THEN dsp.curr_amount 
    ELSE 
    (SELECT mtr.USD_tax_rate 
    FROM mst_tax_rate mtr) * (curr_amount * (conv_rate/(SELECT mcr.conv_rate 
                  FROM mst_currencies_rate mcr 
                  WHERE mcr.curr_code = 'USD'))) END conv_taxrate_commission, 
    CASE WHEN mcr.curr_type = 'LOCAL' 
    THEN dsp.curr_amount 
    ELSE (SELECT mtr.USD_tax_rate 
     FROM mst_tax_rate mtr) * (curr_amount * (conv_rate/(SELECT mcr.conv_rate 
                   FROM mst_currencies_rate mcr 
                   WHERE mcr.curr_code = 'USD'))) 
    END                       final_conv_rate 
FROM 
    dtl_sr ds 
    INNER JOIN dtl_sr_payment dsp ON dsp.flight_id = ds.flight_id 
            AND dsp.sr_id = ds.SR_ID 
    INNER JOIN mst_currencies_rate mcr ON mcr.curr_id = dsp.curr_id