if-statement: if else sql with additional information

dimanche 13 juin 2021

i have a case that the new column in sql contain of additional information, this is example

  A  |      B
  2     Increase 2
 -3     Decrease -3
  0     Not changed
 Null   Not changed

anyone can help me to solve this B column that use if-else statement, i have tried with this code

if(a>0, "increase"+a, "decrease"+a) as B

but i get error. anyone can help me please? thank you in advance

if-statement