The ASIN function returns an arc sine value of the argument. That is, it returns a value whose sine is x in radian. The return value is a DOUBLE type. x must be a value between -1 and 1, inclusive. Otherwise, NULL is returned.
ASIN ( x )
SELECT ASIN(1), ASIN(0), ASIN(-1);
asin(1) asin(0) asin(-1)
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1.570796326794897e+00 0.000000000000000e+00 -1.570796326794897e+00