php mysql insert with where子句选择多个

Question

I have a following

Table1 : userid, who, share, date  :: id is auto increment and primary key

I would like to build a query to check if record exist and insert new record if is empty. How to build this in a single query and insert multiple records using a single query

data to inser ('a1','a2','a3','a4'), ('b1','b2','b3','b4'), ('c1','c2','c3','c4'), .......

Answer 1

1. Create UNIQUE index on column that you want to be unique
2. Use INSERT IGNORE to insert unique data and ignore not unique