You must set the field to “primary key” (PRIMARY KEY) or “only 1 constraint (UNIQUE)” when using both methods below. 1: use REPLACE INTO (this method makes use of the substitution method, which is similar to the method of first deleting and then inserting)

REPLACE INTO Syntax 
REPLACE [LOW_PRIORITY | DELAYED] 
    [INTO] tbl_name [(col_name,...)] 
    {VALUES | VALUE} ({expr | DEFAULT}, ... ),( ... ), ...  
Or: 
REPLACE [LOW_PRIORITY | DELAYED] 
    [INTO] tbl_name 
    SET col_name={expr | DEFAULT},  ...  
Or: 
REPLACE [LOW_PRIORITY | DELAYED] 
    [INTO] tbl_name [(col_name,...)] 
    SELECT  ...

2: use INSERT [IGNORE] INTO (this method is more efficient, judge whether it exists, do not insert if there exists, otherwise insert)

INSERT [IGNORE] INTO Syntax 
INSERT [LOW_PRIORITY | DELAYED | HIGH_PRIORITY] [IGNORE] 
[INTO] tbl_name [(col_name,...)] 
{VALUES | VALUE} ({expr [...]