[mybatis] pk 증가 및 insert

<insert id="saveInfo" parameterType="HashMap">
<selectKey resultType="java.lang.String" keyProperty="FTR_IDS" order="BEFORE">
    SELECT NVL(MAX (FTR_IDS), 0) + 1 FROM WTL_LEAK_PS
</selectKey>
MERGE INTO WTL_LEAK_PS
USING DUAL ON( FTR_IDS = TO_NUMBER(#{FTR_IDS}) )
	WHEN MATCHED THEN
		UPDATE SET FTR_IDN = LPAD(#{FTR_IDS}, 6, '0'),  	
			LOC_CODE=#{LOC_CODE}
			,MDFY_YN=#{MDFY_YN}
			,LEK_IDN=#{LEK_IDN}
			,CANO=#{CANO}
	WHEN NOT MATCHED THEN
		INSERT
		(
		  	LOC_CODE
			,FTR_IDN
			,MDFY_YN
			,LEK_IDN
			,CANO
			, FTR_IDS
		)
		VALUES
		(
		  	 #{LOC_CODE}
			,LPAD(#{FTR_IDS}, 6, '0')
			,#{MDFY_YN}
			,#{LEK_IDN}
			,#{CANO}
			,#{FTR_IDS}
		)  	
 </insert>