fix: issue1875

src/main/java/net/sf/jsqlparser/statement/alter/Alter.java

@@ -24,6 +24,8 @@ public class Alter implements Statement {
  private Table table;
  private boolean useOnly = false;
 
+ private boolean useTableIfExists = false;
+
  private List<AlterExpression> alterExpressions;
 
  public Table getTable() {
@@ -42,6 +44,19 @@ public void setUseOnly(boolean useOnly) {
  this.useOnly = useOnly;
  }
 
+ public boolean isUseTableIfExists() {
+ return useTableIfExists;
+ }
+
+ public void setUseTableIfExists(boolean useTableIfExists) {
+ this.useTableIfExists = useTableIfExists;
+ }
+
+ public Alter withUseTableIfExists(boolean useTableIfExists) {
+ this.useTableIfExists = useTableIfExists;
+ return this;
+ }
+
  public void addAlterExpression(AlterExpression alterExpression) {
  if (alterExpressions == null) {
  alterExpressions = new ArrayList<AlterExpression>();
@@ -71,7 +86,7 @@ public String toString() {
  b.append("ONLY ");
  }
 
- if (alterExpressions.size()>0 && alterExpressions.get(0).getOperation()==AlterOperation.RENAME_TABLE && alterExpressions.get(0).isUsingIfExists()) {
+ if (useTableIfExists) {
  b.append("IF EXISTS ");
  }
 
@@ -108,13 +123,15 @@ public Alter withAlterExpressions(List<AlterExpression> alterExpressions) {
  }
 
  public Alter addAlterExpressions(AlterExpression... alterExpressions) {
- List<AlterExpression> collection = Optional.ofNullable(getAlterExpressions()).orElseGet(ArrayList::new);
+ List<AlterExpression> collection =
+ Optional.ofNullable(getAlterExpressions()).orElseGet(ArrayList::new);
  Collections.addAll(collection, alterExpressions);
  return this.withAlterExpressions(collection);
  }
 
  public Alter addAlterExpressions(Collection<? extends AlterExpression> alterExpressions) {
- List<AlterExpression> collection = Optional.ofNullable(getAlterExpressions()).orElseGet(ArrayList::new);
+ List<AlterExpression> collection =
+ Optional.ofNullable(getAlterExpressions()).orElseGet(ArrayList::new);
  collection.addAll(alterExpressions);
  return this.withAlterExpressions(collection);
  }

src/main/java/net/sf/jsqlparser/statement/alter/AlterExpression.java

@@ -70,6 +70,8 @@ public class AlterExpression implements Serializable {
 
  private String truncatePartitionName = null;
 
+ private boolean useIfNotExists = false;
+
  public Index getOldIndex() {
  return oldIndex;
  }
@@ -417,6 +419,19 @@ public AlterExpression withTruncatePartitionName(String truncatePartitionName) {
  return this;
  }
 
+ public boolean isUseIfNotExists() {
+ return useIfNotExists;
+ }
+
+ public void setUseIfNotExists(boolean useIfNotExists) {
+ this.useIfNotExists = useIfNotExists;
+ }
+
+ public AlterExpression withUserIfNotExists(boolean userIfNotExists) {
+ this.useIfNotExists = userIfNotExists;
+ return this;
+ }
+
  @Override
  @SuppressWarnings({"PMD.CyclomaticComplexity", "PMD.NPathComplexity",
  "PMD.ExcessiveMethodLength", "PMD.SwitchStmtsShouldHaveDefault"})
@@ -493,6 +508,10 @@ public String toString() {
  if (hasColumn) {
  b.append("COLUMN ");
  }
+ if (useIfNotExists
+ && operation == AlterOperation.ADD) {
+ b.append("IF NOT EXISTS ");
+ }
  }
  if (useBrackets && colDataTypeList.size() == 1) {
  b.append(" ( ");

src/main/jjtree/net/sf/jsqlparser/parser/JSqlParserCC.jjt

@@ -6293,7 +6293,7 @@ AlterExpression AlterExpression():
  |
  LOOKAHEAD(3) (
  ( LOOKAHEAD(2) <K_COLUMN> { alterExp.hasColumn(true); } )?
-
+ [ <K_IF> <K_NOT> <K_EXISTS> { alterExp.setUseIfNotExists(true); } ]
  (
  LOOKAHEAD(4) (
  "(" 
@@ -6625,14 +6625,10 @@ Alter AlterTable():
 {
  <K_TABLE>
  [ <K_ONLY> { alter.setUseOnly(true); } ]
- [ LOOKAHEAD(2) <K_IF> <K_EXISTS> { usingIfExists = true; } ]
-
+ [ LOOKAHEAD(2) <K_IF> <K_EXISTS> { alter.setUseTableIfExists(true); } ]
  table=Table() { alter.setTable(table); }
 
- alterExp=AlterExpression() { if (usingIfExists)
- alter.addAlterExpression( alterExp.withUsingIfExists(true) );
- else
- alter.addAlterExpression(alterExp); }
+ alterExp=AlterExpression() { alter.addAlterExpression(alterExp); }
 
  ("," alterExp=AlterExpression() { alter.addAlterExpression(alterExp); } )*
 

src/test/java/net/sf/jsqlparser/statement/alter/AlterTest.java

@@ -988,4 +988,11 @@ public void testIssue1890() throws JSQLParserException {
  "ALTER TABLE xdmiddle.ft_mid_sop_sms_send_list_daily TRUNCATE PARTITION sum_date";
  assertSqlCanBeParsedAndDeparsed(stmt);
  }
+
+ @Test
+ public void testIssue1875() throws JSQLParserException {
+ String stmt =
+ "ALTER TABLE IF EXISTS usercenter.dict_surgeries ADD COLUMN IF NOT EXISTS operation_grade_id int8 NULL";
+ assertSqlCanBeParsedAndDeparsed(stmt);
+ }
 }