unstable test TestIfFunctionWithNull

[hawkingrei]

Bug Report

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1. Minimal reproduce step (Required)

2. What did you expect to see? (Required)

3. What did you see instead (Required)

[2023/05/29 08:30:16.274 +08:00] [INFO] [callback.go:128] ["performing DDL change, must reload"]
    result.go:49: 
        	Error Trace:	testkit/result.go:49
        	            				expression/integration_test/integration_test.go:7946
        	Error:      	Not equal: 
        	            	expected: "[20000 35100]\n"
        	            	actual  : "[<nil> 35100]\n"
        	            	
        	            	Diff:
        	            	--- Expected
        	            	+++ Actual
        	            	@@ -1,2 +1,2 @@
        	            	-[20000 35100]
        	            	+[<nil> 35100]
        	            	 
        	Test:       	TestIfFunctionWithNull
        	Messages:   	sql:select min(if(apply_to_now_days <= 30,loan,null)) as min, max(if(apply_to_now_days <= 720,loan,null)) as max from (select loan, datediff(from_unixtime(unix_timestamp() + 18000), from_unixtime(apply_time/1000 + 18000)) as apply_to_now_days from orders) t1;, args:[]

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