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1. IF-ELSE Óï¾ä

IF (condition) THEN statement1
ELSE statement2

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condition£ºÒªÆÀ¹ÀµÄÌõ¼þ¡£

statement1£ºÈôÊÇÌõ¼þΪÕæ £¬ÔòÖ´ÐеÄÓï¾ä¡£

statement2£ºÈôÊÇÌõ¼þΪ¼Ù £¬ÔòÖ´ÐеÄÓï¾ä¡£

2. CASE Óï¾ä

CASE
  WHEN condition1 THEN result1
  WHEN condition2 THEN result2
  ...
  ELSE default_result
END

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condition1, condition2, …£ºÒªÆÀ¹ÀµÄÌõ¼þ¡£

result1, result2, …£ºÈôÊÇÏìÓ¦Ìõ¼þΪÕæ £¬Ôò·µ»ØµÄЧ¹û¡£

default_result£ºÈôÊÇËùÓÐÌõ¼þ¶¼Îª¼Ù £¬Ôò·µ»ØµÄĬÈÏЧ¹û£¨¿ÉÑ¡£©¡£

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IF-ELSE Óï¾ä

IF (age > 18) THEN
  PRINT "³ÉÄê"
ELSE
  PRINT "δ³ÉÄê"

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CASE Óï¾ä

CASE
  WHEN gender = 'M' THEN "ÄÐÐÔ"
  WHEN gender = 'F' THEN "Å®ÐÔ"
  ELSE "ÆäËû"
END

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